fix bug

data/1.MySQL初阶/2.安装和登录/2.登录/prepare.md

@@ -24,7 +24,7 @@ sudo su
 mysql mysql
 ```
 创建数据库用户 joe 并授权：
-```mysql
+```sql
 create user 'joe'@'localhost' identified by 'joe';
 grant all privileges on *.* to `joe`@`localhost`;
 flush privileges ;
@@ -40,7 +40,7 @@ flush privileges ;
 mysql mysql
 ```
 为 joe 授权
-```mysql
+```sql
 grant all privileges on *.* to joe;
 flush privileges ;
 ```
@@ -54,7 +54,7 @@ mysql mysql
 ```
 
 为 joe 授权
-```mysql
+```sql
 grant all privileges on *.* to joe;
 flush privileges ;
 ```
@@ -67,7 +67,7 @@ mysql mysql
 ```
 
 创建数据库用户 joe
-```mysql
+```sql
 create user 'joe'@'localhost' identified by 'joe';
 flush privileges ;
 ```
@@ -80,7 +80,7 @@ sudo su
 mysql mysql
 ```
 创建数据库用户 joe 并授权：
-```mysql
+```sql
 create user 'joe'@'%' identified by 'joe';
 grant all privileges on *.* to joe;
 flush privileges ;

data/1.MySQL初阶/3.使用数据库/1. 创建和删除数据库/create_database.md

@@ -11,7 +11,7 @@ Joe 在开发机上创建了一个名为 goods 的数据库，做了一些练习
 
 ## 答案
 
-```mysql
+```sql
 drop database goods;
 create database goods;
 ```
@@ -20,14 +20,14 @@ create database goods;
 
 ### A
 
-```mysql
+```sql
 delete database goods;
 create database goods;
 ```
 
 ### B
 
-```mysql
+```sql
 if exists(database goods) then
 begin 
     drop database goods;
@@ -37,7 +37,7 @@ create database goods;
 
 ### C
 
-```mysql
+```sql
 use goods;
 drop database goods;
 create database goods;
@@ -45,7 +45,7 @@ create database goods;
 
 ### D
 
-```mysql
+```sql
 use goods;
 drop database goods;
 make database goods;
@@ -53,14 +53,14 @@ make database goods;
 
 ### E
 
-```mysql
+```sql
 drop database goods;
 make database goods;
 ```
 
 ### F
 
-```mysql
+```sql
 cd goods;
 drop database goods;
 create database goods;

data/1.MySQL初阶/3.使用数据库/2.创建和删除表/auto_increment.md

@@ -11,7 +11,7 @@ Joe 需要重建一个 id 为自增字段的 goods_category 。他已经删除
 
 ## 答案
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT PRIMARY KEY AUTO_INCREMENT,
@@ -24,7 +24,7 @@ CREATE TABLE goods_category
 
 ### A
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT PRIMARY KEY SERIALS,
@@ -35,7 +35,7 @@ CREATE TABLE goods_category
 
 ### B
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT ,
@@ -48,7 +48,7 @@ CREATE TABLE goods_category
 
 ### C
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT PRIMARY KEY,
@@ -59,7 +59,7 @@ CREATE TABLE goods_category
 
 ### D
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT PRIMARY KEY SERIALS,

data/1.MySQL初阶/3.使用数据库/2.创建和删除表/create_table.md

@@ -11,7 +11,7 @@ Joe 想要在 goods 数据库创建一个 goods_category 表，管理商品的
 
 ## 答案
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT PRIMARY KEY ,
@@ -24,7 +24,7 @@ CREATE TABLE goods_category
 
 ### A
 
-```mysql
+```sql
 MAKE TABLE goods_category
 (
     id         INT PRIMARY KEY ,
@@ -35,7 +35,7 @@ MAKE TABLE goods_category
 
 ### B
 
-```mysql
+```sql
 DROP TABLE goods_category
 (
     id         INT PRIMARY KEY,
@@ -46,7 +46,7 @@ DROP TABLE goods_category
 
 ### C
 
-```mysql
+```sql
 SAVE TABLE goods_category
 (
     id         INT PRIMARY KEY,
@@ -57,7 +57,7 @@ SAVE TABLE goods_category
 
 ### D
 
-```mysql
+```sql
 ADD TABLE goods_category
 (
     id         INT PRIMARY KEY,
@@ -68,7 +68,7 @@ ADD TABLE goods_category
 
 ### E
 
-```mysql
+```sql
 PUT TABLE goods_category
 (
     id         INT PRIMARY KEY,

data/1.MySQL初阶/3.使用数据库/2.创建和删除表/drop_table.md

@@ -11,7 +11,7 @@ Joe 想要删除数据库中的 good_category 表，他应该怎么操作？
 
 ## 答案
 
-```mysql
+```sql
 drop table goods_category;
 ```
 
@@ -19,30 +19,30 @@ drop table goods_category;
 
 ### A
 
-```mysql
+```sql
 delete table good_category;
 ```
 
 ### B
 
-```mysql
+```sql
 delete table where name = 'good_category';
 ```
 
 ### C
 
-```mysql
+```sql
 remove table good_category;
 ```
 
 ### D
 
-```mysql
+```sql
 truncate table goods_category;
 ```
 
 ### E
 
-```mysql
+```sql
 clean table goods_category;
 ```

data/1.MySQL初阶/3.使用数据库/4.存储引擎/engine.md

@@ -11,7 +11,7 @@ Joe 需要确保 goods_category 表的存储引擎为 innodb ，那么建表语
 
 ## 答案
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT,
@@ -24,7 +24,7 @@ CREATE TABLE goods_category
 
 ### A
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT,
@@ -35,7 +35,7 @@ CREATE TABLE goods_category
 
 ### B
 
-```mysql
+```sql
 WITH ENGINE=INNODB CREATE TABLE goods_category
 (
     id         INT,
@@ -46,7 +46,7 @@ WITH ENGINE=INNODB CREATE TABLE goods_category
 
 ### C
 
-```mysql
+```sql
 SAVE TABLE goods_category
 (
     id         INT,
@@ -57,7 +57,7 @@ SAVE TABLE goods_category
 
 ### D
 
-```mysql
+```sql
 CREATE TABLE goods_category
 (
     id         INT,

data/1.MySQL初阶/4.数据类型/1.数值类型/numbers.md

@@ -9,7 +9,7 @@ Joe 需要使用下列表做一项数值计算
 * `show databases;` 列出所有数据库
 * `show tables;` 列出所有表
 
-```mysql
+```sql
 create table points(
     id int primary key auto_increment,
     x int,
@@ -19,7 +19,7 @@ create table points(
 
 计算查询为：
 
-```mysql
+```sql
 select id, (x^2 + y^2)/2 as result from points;
 ```
 

data/1.MySQL初阶/4.数据类型/2.日期和时间类型/datetime.md

@@ -2,7 +2,7 @@
 
 Joe 写了一个订单表的创建语句：
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -23,7 +23,7 @@ create table orders (
 
 ## 答案
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -38,7 +38,7 @@ create table orders (
 
 ### A
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -51,7 +51,7 @@ create table orders (
 
 ### B
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -64,7 +64,7 @@ create table orders (
 
 ### C
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -77,7 +77,7 @@ create table orders (
 
 ### D
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,

data/1.MySQL初阶/4.数据类型/3.文本字符串类型/description.md

@@ -2,7 +2,7 @@
 
 Joe 在设计订单表，他已经完成了下列内容：
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -24,7 +24,7 @@ create table orders (
 
 ## 答案
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -40,7 +40,7 @@ create table orders (
 
 ### A
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -54,7 +54,7 @@ create table orders (
 
 ### B
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -68,7 +68,7 @@ create table orders (
 
 ### C
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -82,7 +82,7 @@ create table orders (
 
 ### D
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,

data/1.MySQL初阶/4.数据类型/4.二进制字符串类型/binary.md

@@ -2,7 +2,7 @@
 
 现在 Joe 的订单表已经有了如下形态：
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -25,7 +25,7 @@ create table orders (
 
 ## 答案
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -42,7 +42,7 @@ create table orders (
 
 ### A
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -57,7 +57,7 @@ create table orders (
 
 ### B
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -72,7 +72,7 @@ create table orders (
 
 ### C
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,
@@ -87,7 +87,7 @@ create table orders (
 
 ### D
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     item_id int,

data/1.MySQL初阶/5.数据修改/1.插入/insert.md

@@ -2,7 +2,7 @@
 
 Goods 数据库中有一个表：
 
-```mysql
+```sql
 create table book(
     id int primary key auto_increment,
     title varchar(200) not null ,
@@ -25,7 +25,7 @@ create unique index idx_book_isbn on book(isbn);
 
 ## 答案
 
-```mysql
+```sql
 insert into book(title, price, isbn, publish_at) select 'a book title', 25.4, 'xx-xxxx-xxxx', '2019-12-1';
 insert into book(title, price, isbn, publish_at) select 'a other book title', 25.4, 'yy-yyyy-xxxx', '2019-12-1'; 
 ```
@@ -34,28 +34,28 @@ insert into book(title, price, isbn, publish_at) select 'a other book title', 25
 
 ### 唯一键冲突
 
-```mysql
+```sql
 insert into book(title, price, isbn, publish_at) select 'a book title', 25.4, 'xx-xxxx-xxxx', '2019-12-1';
 insert into book(title, price, isbn, publish_at) select 'a other book title', 35.4, 'xx-xxxx-xxxx', '2019-12-1'; 
 ```
 
 ### 缺少必要的列
 
-```mysql
+```sql
 insert into book(price, isbn, publish_at) select 25.4, 'xx-xxxx-xxxx', '2019-12-1';
 insert into book(price, isbn, publish_at) select 35.4, 'yy-yyyy-xxxx', '2019-12-1';
 ```
 
 ### 类型错误
 
-```mysql
+```sql
 insert into book(title, price, isbn, publish_at) select 'a book title', 'unknown', 'xx-xxxx-xxxx', '2019-12-1';
 insert into book(title, price, isbn, publish_at) select 'a other book title', 'unknown', 'xx-xxxx-xxxx', '2019-12-1';
 ```
 
 ### 违反非空约束
 
-```mysql
+```sql
 insert into book(title, price, isbn, publish_at) select null, 'unknown', 'xx-xxxx-xxxx', '2019-12-1';
 insert into book(title, price, isbn, publish_at) select null, 'unknown', 'xx-xxxx-xxxx', '2019-12-1';
 ```

data/1.MySQL初阶/5.数据修改/2.修改/update.md

@@ -2,7 +2,7 @@
 
 现有 employee 表如下：
 
-```mysql
+```sql
 create table employee
 (
     id serial primary key,
@@ -23,7 +23,7 @@ Joe 希望修改销售部(dept 字段为 sale)员工 Dora Muk 的工资，将其
 
 ## 答案
 
-```mysql
+```sql
 update employee set salary = salary + 1000 where dept = 'sale' and name = 'Dora Muk';
 ```
 
@@ -31,20 +31,20 @@ update employee set salary = salary + 1000 where dept = 'sale' and name = 'Dora
 
 ### 过滤条件不严谨
 
-```mysql
+```sql
 update employee set salary = salary + 1000 where name = 'Dora Muk';
 ```
 
 
 ### 缺少过滤条件
 
-```mysql
+```sql
 update employee set salary = salary + 1000;
 ```
 
 ### 错误的赋值语句
 
-```mysql
+```sql
 update employee set salary += 1000;
 ```
 

data/1.MySQL初阶/5.数据修改/3.删除/delete.md

@@ -2,7 +2,7 @@
 
 现在 orders 表结构如下：
 
-```mysql
+```sql
 create table orders (
                         id int primary key auto_increment,
                         item_id int,
@@ -28,7 +28,7 @@ create table orders (
 
 在一个独立的定时任务中执行
 
-```mysql
+```sql
 delete
 from orders
 where deal;
@@ -40,7 +40,7 @@ where deal;
 
 在一个独立的定时任务中执行
 
-```mysql
+```sql
 truncate orders;
 ```
 
@@ -48,7 +48,7 @@ truncate orders;
 
 在一个独立的定时任务中执行
 
-```mysql
+```sql
 delete
 from orders;
 ```
@@ -57,7 +57,7 @@ from orders;
 
 在一个独立的定时任务中执行
 
-```mysql
+```sql
 drop table orders;
 create table if not exists orders (
                         id int primary key auto_increment,
@@ -75,7 +75,7 @@ create table if not exists orders (
 
 建立视图
 
-```mysql
+```sql
 create view order_view as
 select id, meta, content, created_at
 from orders
@@ -88,7 +88,7 @@ where not deal;
 
 在一个独立的定时任务中执行
 
-```mysql
+```sql
 delete
 from orders
 where deal;

data/1.MySQL初阶/6.数据查询/1.SELECT/select.md

@@ -11,7 +11,7 @@
 
 ## 答案
 
-```mysql
+```sql
 from test select abc;
 ```
 
@@ -20,31 +20,31 @@ from test select abc;
 
 ### A
 
-```mysql
+```sql
 select 3.14;
 ```
 
 ### B
 
-```mysql
+```sql
 select * from employee;
 ```
 
 ### C
 
-```mysql
+```sql
 select * from employee where dept = 'hr';
 ```
 
 ### D
 
-```mysql
+```sql
 select id, name, dept, salary from employee where salary > 10000;
 ```
 
 ### E
 
-```mysql
+```sql
 select now();
 ```
 

data/1.MySQL初阶/6.数据查询/2.WHERE/where.md

@@ -2,7 +2,7 @@
 
 Joe 希望从 orders 表
 
-```mysql
+```sql
 create table orders
 (
     id          int primary key auto_increment,
@@ -27,7 +27,7 @@ create table orders
 
 ## 答案
 
-```mysql
+```sql
 select id
 from orders
 where date(ts) = '2022-05-25'
@@ -38,7 +38,7 @@ where date(ts) = '2022-05-25'
 
 ### A
 
-```mysql
+```sql
 select id
 from (select * from orders where date(ts) = '2022-05-25') as o
 where unit_prise < 20;
@@ -46,7 +46,7 @@ where unit_prise < 20;
 
 ### B
 
-```mysql
+```sql
 select id
 from orders
 where date(ts) = '2022-05-25'
@@ -55,7 +55,7 @@ where date(ts) = '2022-05-25'
 
 ### C
 
-```mysql
+```sql
 select id
 from orders 
 if date(ts) = '2022-05-25' or unit_prise < 20;
@@ -63,7 +63,7 @@ if date(ts) = '2022-05-25' or unit_prise < 20;
 
 ### D
 
-```mysql
+```sql
 select id
 from orders
 which date(ts) = '2022-05-25'

data/1.MySQL初阶/6.数据查询/3.运算符/geo.md

@@ -2,7 +2,7 @@
 
 Points 表结构如下：
 
-```mysql
+```sql
 create table points(
     id int primary key auto_increment,
     x float,
@@ -21,7 +21,7 @@ create table points(
 
 ## 答案
 
-```mysql
+```sql
 select id, sqrt(x^2 + y^2) from points;
 ```
 
@@ -29,24 +29,24 @@ select id, sqrt(x^2 + y^2) from points;
 
 ### A
 
-```mysql
+```sql
 select sqrt(vx+vy) from (select x^2 as vx, y^2 as vy from points) as t;
 ```
 
 ### B
 
-```mysql
+```sql
 select sqrt(vx + vy) from points where x^2 as vx, y^2 as vy ;
 ```
 
 ### C
 
-```mysql
+```sql
 select id + sqrt(x^2 + y^2) from points;
 ```
 
 ### D
 
-```mysql
+```sql
 select id || sqrt(x^2 + y^2) from points;
 ```
\ No newline at end of file

data/2.MySQL中阶/1.数据库组成/1.表/create_table.md

@@ -12,7 +12,7 @@
 
 ## 答案
 
-```mysql
+```sql
 create table trade (
     id int primary key auto_increment,
     content varchar(8000),
@@ -24,7 +24,7 @@ create table trade (
 
 ### 主键没有设置自增，不符合题意
 
-```mysql
+```sql
 create table trade (
     id integer primary key,
     content varchar(8000),
@@ -34,7 +34,7 @@ create table trade (
 
 ### 时间戳没有设置默认值
 
-```mysql
+```sql
 create table trade (
     id serial primary key,
     content varchar(8000),
@@ -44,7 +44,7 @@ create table trade (
 
 ###  没有主键，不符合题设
 
-```mysql
+```sql
 create table trade (
     id serial,
     content varchar(8000),

data/2.MySQL中阶/1.数据库组成/2.视图/view.md

@@ -2,7 +2,7 @@
 
 Joe 需要给 goods 表
 
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category_id int,
@@ -25,7 +25,7 @@ create table goods(
 
 ## 答案
 
-```mysql
+```sql
 CREATE VIEW view_name_price 
     AS 
     SELECT name, price 
@@ -37,7 +37,7 @@ CREATE VIEW view_name_price
 
 ### A
 
-```mysql
+```sql
 CREATE VIEW view_name_price 
     AS 
     SELECT name, price 
@@ -46,7 +46,7 @@ CREATE VIEW view_name_price
 
 ### B
 
-```mysql
+```sql
 CREATE VIEW view_name_price 
     AS 
     SELECT * 
@@ -56,7 +56,7 @@ CREATE VIEW view_name_price
 
 ### C
 
-```mysql
+```sql
 CREATE VIEW view_name_price
     AS 
 BEGIN
@@ -68,7 +68,7 @@ END;
 
 ### D
 
-```mysql
+```sql
 CREATE VIEW view_name_price
     AS 
 BEGIN

data/2.MySQL中阶/1.数据库组成/3.存储过程和函数/create_function.md

@@ -12,7 +12,7 @@
 
 ## 答案
 
-```mysql
+```sql
 create function individual_income_tax(salary decimal(12, 4)) returns decimal(12, 4)
 deterministic
 begin 
@@ -24,7 +24,7 @@ end;
 
 ### A
 
-```mysql
+```sql
 create store function individual_income_tax(salary decimal(12, 4)) returns decimal(12, 4)
     deterministic
 begin 
@@ -34,7 +34,7 @@ end;
 
 ### B
 
-```mysql
+```sql
 create function individual_income_tax(salary decimal(12, 4))
     deterministic
 begin 
@@ -45,7 +45,7 @@ end;
 
 ### C
 
-```mysql
+```sql
 create function decimal(12, 4) individual_income_tax(salary decimal(12, 4))
 begin 
     -- ...

data/2.MySQL中阶/1.数据库组成/3.存储过程和函数/create_procedure.md

@@ -13,7 +13,7 @@ Joe 希望这个计算更紧凑一些，在已经有 individual_income_tax 的
 
 ## 答案
 
-```mysql
+```sql
 create procedure sp_idt(in salary decimal(12, 4), out tax decimal(12, 4), out take_home decimal(12, 4)) 
 begin 
     set tax = individual_income_tax(salary);
@@ -25,7 +25,7 @@ end;
 
 ### A
 
-```mysql
+```sql
 create procedure sp_idt(salary decimal(12, 4)) returns (tax decimal(12, 4), take_home decimal(12, 4))
 begin 
     set tax = individual_income_tax(salary);
@@ -36,7 +36,7 @@ end;
 ### B
 
 
-```mysql
+```sql
 create procedure sp_idt(salary decimal(12, 4)) returns (decimal(12, 4), decimal(12, 4))
 begin 
     declare tax, take_home decimal(12, 4);
@@ -48,7 +48,7 @@ end;
 
 ### C
 
-```mysql
+```sql
 create procedure sp_idt(in salary decimal(12, 4), out tax decimal(12, 4), out take_home decimal(12, 4)) returns void
 begin 
     set tax = individual_income_tax(salary);
@@ -58,7 +58,7 @@ end;
 
 ### D
 
-```mysql
+```sql
 create procedure sp_idt(in salary decimal(12, 4)) 
 begin
     declare tax, take_home decimal(12, 4);

data/2.MySQL中阶/1.数据库组成/3.存储过程和函数/drop_function.md

@@ -11,7 +11,7 @@ Joe 将计税逻辑放到了 sp_idt 中，现在不需要 individual_income_tax
 
 ## 答案
 
-```mysql
+```sql
 drop function individual_income_tax;
 ```
 
@@ -19,20 +19,20 @@ drop function individual_income_tax;
 
 ### A
 
-```mysql
+```sql
 delete function individual_income_tax;
 ```
 
 ### B
 
-```mysql
+```sql
 remove function individual_income_tax;
 ```
 
 
 ### C
 
-```mysql
+```sql
 drop function individual_income_tax(decimal(12, 4));
 ```
 

data/2.MySQL中阶/1.数据库组成/4.索引和约束/unique.md

@@ -2,7 +2,7 @@
 
 现有一个图书登记表：
 
-```mysql
+```sql
 create table book(
     id int primary key auto_increment,
     title text,

data/2.MySQL中阶/1.数据库组成/4.索引和约束/unique_2.md

@@ -2,7 +2,7 @@
 
 现有一个图书登记表：
 
-```mysql
+```sql
 create table book(
     id int primary key auto_increment,
     title text,

data/2.MySQL中阶/1.数据库组成/5. 触发器/audit.md

@@ -2,7 +2,7 @@
 
 Orders 表
 
-```mysql
+```sql
 create table orders
 (
     id          int primary key auto_increment,
@@ -17,7 +17,7 @@ create table orders
 
 记录了未完成的订单。审计部门现在需要记录其变更——新增或删除,该表不会发生update——即将修改都记录到 orders_log 表
 
-```mysql
+```sql
 create table orders_log
 (
     log_id          int primary key auto_increment,
@@ -44,7 +44,7 @@ create table orders_log
 
 ## 答案
 
-```mysql
+```sql
 create trigger in_orders after insert on orders
     for each row insert into orders_log(id, item_id, amount, unit_price, total, description, ts, direction)
     values(NEW.id, NEW.item_id, NEW.amount, NEW.unit_price, NEW.total, NEW.description, NEW.ts, 'in');
@@ -58,7 +58,7 @@ create trigger out_orders after delete on orders
 
 ### A
 
-```mysql
+```sql
 create trigger in_orders after insert on orders
     for each row insert into orders_log(id, item_id, amount, unit_price, total, description, ts, direction)
     values(NEW.id, NEW.item_id, NEW.amount, NEW.unit_price, NEW.total, NEW.description, NEW.ts, 'in');
@@ -67,7 +67,7 @@ create trigger in_orders after insert on orders
 
 ### B
 
-```mysql
+```sql
 
 create trigger out_orders after delete on orders
     for each row insert into orders_log(id, item_id, amount, unit_price, total, description, ts, direction)
@@ -77,7 +77,7 @@ create trigger out_orders after delete on orders
 
 ### C
 
-```mysql
+```sql
 create trigger in_orders after insert on orders
         for each row insert into orders_log(id, item_id, amount, unit_price, total, description, ts, direction)
         values(NEW.id, NEW.item_id, NEW.amount, NEW.unit_price, NEW.total, NEW.description, NEW.ts, 'in');
@@ -88,7 +88,7 @@ create trigger in_orders after insert on orders
 
 ### D
 
-```mysql
+```sql
 create trigger in_orders after insert, after delete on orders
     for each row insert into orders_log(id, item_id, amount, unit_price, total, description, ts, direction)
     values(NEW.id, NEW.item_id, NEW.amount, NEW.unit_price, NEW.total, NEW.description, NEW.ts, 'in');

data/2.MySQL中阶/1.数据库组成/5. 触发器/trigger.md

@@ -2,7 +2,7 @@
 
 SmartMarket 公司的OA数据库中包含以下结构：
 
-```mysql
+```sql
 create table employee(
     id serial primary key ,
     name varchar(256),

data/2.MySQL中阶/1.数据库组成/6.存储引擎/upgrade_engine.md

@@ -11,7 +11,7 @@ Goods 表的存储引擎是 MyISAM，Joe 需要把它修改为 InnoDB，他应
 
 ## 答案
 
-```mysql
+```sql
 alter table goods engine innodb;
 ```
 
@@ -19,7 +19,7 @@ alter table goods engine innodb;
 
 ### A
 
-```mysql
+```sql
 alter table goods set engine innodb;
 ```
 
@@ -31,7 +31,7 @@ alter table goods set engine innodb;
 
 ### C
 
-```mysql
+```sql
 alter table goods add engine innodb;
 ```
 

data/2.MySQL中阶/10.用户和权限/1.创建普通用户/create_user.md

@@ -12,7 +12,7 @@ Joe 要给数据组的 John 创建一个用户，他希望John 能够从 `192.16
 
 ## 答案
 
-```mysql
+```sql
 create user 'john'@'192.168.7.42' identified by 'goods123' password expire;
 grant select on goods.* to 'john'@'192.168.7.42';
 flush privileges;
@@ -22,7 +22,7 @@ flush privileges;
 
 ### A
 
-```mysql
+```sql
 create user 'john'@'192.168.7.42' identified by 'goods123';
 grant select on goods.* to 'john'@'192.168.7.42';
 flush privileges;
@@ -30,7 +30,7 @@ flush privileges;
 
 ### B
 
-```mysql
+```sql
 create user 'john'@'192.168.7.42' identified by 'goods123';
 grant usage on goods.* to 'john'@'192.168.7.42';
 flush privileges;
@@ -38,7 +38,7 @@ flush privileges;
 
 ### C
 
-```mysql
+```sql
 create user 'john'@'192.168.7.42' identified by 'goods123' on database goods;
 flush privileges;
 ```
\ No newline at end of file

data/2.MySQL中阶/10.用户和权限/2.为用户授权/grant.md

@@ -11,7 +11,7 @@
 
 ## 答案
 
-```mysql
+```sql
 grant select on table employee to joe;
 ```
 
@@ -19,30 +19,30 @@ grant select on table employee to joe;
 
 ### 权限名错误
 
-```mysql
+```sql
 grant query on table employee to joe;
 ```
 
 ### 权限名错误
 
-```mysql
+```sql
 grant read on table employee to joe;
 ```
 
 ### 操作关键词错误
 
-```mysql
+```sql
 grant select on table employee of joe;
 ```
 
 ### 操作错误
 
-```mysql
+```sql
 grant select on table employee.* of joe;
 ```
 
 ### 权限过高
 
-```mysql
+```sql
 grant all on table employee to joe;
 ```

data/2.MySQL中阶/10.用户和权限/2.为用户授权/role.md

@@ -12,7 +12,7 @@ Joe 现在是团队的 DBA，公司数据分析组有 Fred、Alice、James、Jon
 
 ## 答案
 
-```mysql
+```sql
 create role analysis;
 grant analysis to fred, alice, james, jone;
 grant select on  goods.* to analysis;
@@ -23,13 +23,13 @@ flush privileges;
 
 ### 将来人员变动管理会很繁琐
 
-```mysql
+```sql
 grant select on goods.* to fred, alice, james, jone;
 ```
 
 ### 错误的语法
 
-```mysql
+```sql
 create role analysis;
 grant analysis to fred, alice, james, jone;
 grant all on all tables in schema goods to analysis;
@@ -38,7 +38,7 @@ flush privileges;
 
 ### 过度授权
 
-```mysql
+```sql
 create role analysis;
 grant analysis to fred, alice, james, jone;
 grant select on *.* to analysis;

data/2.MySQL中阶/10.用户和权限/3.查看用户权限/view_privileges.md

@@ -11,7 +11,7 @@ Joe 想要查看 Fred 的 MySQL 账户 `'fred'@'%'` 的权限，他应该怎么
 
 ## 答案
 
-```mysql
+```sql
 show grants for fred;
 ```
 
@@ -19,18 +19,18 @@ show grants for fred;
 
 ### A
 
-```mysql
+```sql
 select grants from fred;
 ```
 
 ### B
 
-```mysql
+```sql
 show privileges for fred;
 ```
 
 ### B
 
-```mysql
+```sql
 show privileges from fred;
 ```

data/2.MySQL中阶/10.用户和权限/4.撤销用户权限/revoke.md

@@ -12,7 +12,7 @@
 
 ## 答案
 
-```mysql
+```sql
 revoke select on trade from fred;
 ```
 
@@ -20,19 +20,19 @@ revoke select on trade from fred;
 
 ### 操作错误
 
-```mysql
+```sql
 grant not select on trade to fred;
 ```
 
 ### 操作关键字错误
 
-```mysql
+```sql
 revoke select on trade to fred;
 ```
 
 ### 指定权限错误
 
-```mysql
+```sql
 revoke owned trade from fred;
 ```
 

data/2.MySQL中阶/10.用户和权限/5.修改用户密码/change_password.md

@@ -13,7 +13,7 @@ Joe 准备将这个账户的口令初始化为 `goods123fred` ，
 
 ## 答案
 
-```mysql
+```sql
 alter user 'fred'@'%' identified by 'goods123fred' password expire;
 ```
 
@@ -21,18 +21,18 @@ alter user 'fred'@'%' identified by 'goods123fred' password expire;
 
 ### A
 
-```mysql
+```sql
 alter user 'fred'@'%' identified by 'goods123fred';
 ```
 
 ### B
 
-```mysql
+```sql
 alter user 'fred'@'%' set password 'goods123fred';
 ```
 
 ### C
 
-```mysql
+```sql
 alter user 'fred'@'%' set password 'goods123fred' expire;
 ```
\ No newline at end of file

data/2.MySQL中阶/10.用户和权限/6.删除用户/drop_user.md

@@ -11,7 +11,7 @@ Jane 从公司离职，Joe 需要从数据库服务器删除她的账号 `'jane'
 
 ## 答案
 
-```mysql
+```sql
 drop user 'jane'@'%';
 ```
 
@@ -19,18 +19,18 @@ drop user 'jane'@'%';
 
 ### A
 
-```mysql
+```sql
 delete user 'jane'@'%';
 ```
 
 ### B
 
-```mysql
+```sql
 remove user 'jane'@'%';
 ```
 
 ### C
 
-```mysql
+```sql
 revoke user 'jane'@'%';
 ```
\ No newline at end of file

data/2.MySQL中阶/10.用户和权限/7.限制用户使用资源/limit_action.md

@@ -11,7 +11,7 @@ Joe 需要限制数据分析组（role analysis）的用户, 每小时查询次
 
 ## 答案
 
-```mysql
+```sql
 alter user analysis with MAX_QUERIES_PER_HOUR 10000;
 ```
 
@@ -19,25 +19,25 @@ alter user analysis with MAX_QUERIES_PER_HOUR 10000;
 
 ### A
 
-```mysql
+```sql
 set user analysis with MAX_QUERIES_PER_HOUR 10000;
 ```
 
 
 ### B
 
-```mysql
+```sql
 alter role analysis with MAX_QUERIES_PER_HOUR 10000;
 ```
 
 ### C
 
-```mysql
+```sql
 alter role analysis with MAX_QUERIES_PER_HOUR=10000;
 ```
 
 ### D
 
-```mysql
+```sql
 alter user analysis set MAX_QUERIES_PER_HOUR 10000;
 ```

data/2.MySQL中阶/2.查询进阶/2. BETWEEN/between.md

 # Between
 
 Joe 要查询 goods 表
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category_id int,
@@ -23,7 +23,7 @@ create table goods(
 
 ## 答案
 
-```mysql
+```sql
 SELECT * FROM goods HAVING price BETWEEN 1000 AND 2000;
 ```
 
@@ -32,19 +32,19 @@ SELECT * FROM goods HAVING price BETWEEN 1000 AND 2000;
 
 ### A
 
-```mysql
+```sql
 SELECT * FROM goods WHERE price BETWEEN 1000 AND 2000;
 ```
 
 ### B
 
-```mysql
+```sql
 SELECT * FROM goods WHERE price >= 1000 AND price <= 2000;
 ```
 
 ### C
 
-```mysql
+```sql
 SELECT * FROM goods WHERE not (price < 1000 or price > 2000);
 ```
 

data/2.MySQL中阶/2.查询进阶/3.CASE/case.md

@@ -2,7 +2,7 @@
 
 Goods 表结构如下
 
-```mysql
+```sql
 create table goods(
                       id int primary key auto_increment,
                       category_id int,
@@ -26,7 +26,7 @@ normal，这个查询应该怎么写？
 
 ## 答案
 
-```mysql
+```sql
 select name,
        case 
            when price < 10 then 'cheap'
@@ -40,7 +40,7 @@ from goods;
 
 ### A
 
-```mysql
+```sql
 select name,
        case price
            when  < 10 then 'cheap'
@@ -52,7 +52,7 @@ from goods;
 
 ### B
 
-```mysql
+```sql
 select name,
        case
            when price < 10  'cheap'
@@ -64,7 +64,7 @@ from goods;
 
 ### C
 
-```mysql
+```sql
 select name,
        case
            when price < 10 then 'cheap'
@@ -76,7 +76,7 @@ from goods;
 
 ### C
 
-```mysql
+```sql
 select name,
        case
            when price < 10 then 'cheap'

data/2.MySQL中阶/2.查询进阶/4.DISTINCT/distinct.md

@@ -2,7 +2,7 @@
 
 Joe 想统计以下 goods 表
 
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category_id int,
@@ -25,7 +25,7 @@ create table goods(
 
 ## 答案
 
-```mysql
+```sql
 select count(distinct price) from goods;
 ```
 
@@ -33,24 +33,24 @@ select count(distinct price) from goods;
 
 ### A
 
-```mysql
+```sql
 select count(distinct *) from goods;
 ```
 
 ### B
 
-```mysql
+```sql
 select distinct count(price) from goods;
 ```
 
 ### C
 
-```mysql
+```sql
 select count(price) from goods;
 ```
 
 ### D
 
-```mysql
+```sql
 select distinct price from goods;
 ```

data/2.MySQL中阶/2.查询进阶/5.ORDER BY/order_by.md

@@ -2,7 +2,7 @@
 
 Joe 需要根据员工表
 
-```mysql
+```sql
 create table employee
 (
     id     serial primary key,
@@ -23,7 +23,7 @@ create table employee
 
 ## 答案
 
-```mysql
+```sql
 select id, name, dept, salary from employee order by dept, salary desc;
 ```
 
@@ -31,29 +31,29 @@ select id, name, dept, salary from employee order by dept, salary desc;
 
 ### A
 
-```mysql
+```sql
 select id, name, dept, salary from employee order by dept, salary;
 ```
 
 ### B
 
-```mysql
+```sql
 select id, name, dept, salary from employee order by dept desc, salary desc;
 ```
 
 ### C
-```mysql
+```sql
 select id, name, dept, salary from employee order by dept and salary desc;
 ```
 
 ### D
 
-```mysql
+```sql
 select id, name, dept, salary from employee order by dept, salary, id, name;
 ```
 
 ### E
-```mysql
+```sql
 select id, name, dept, salary from employee order by dept, salary desc;
 ```
 

data/2.MySQL中阶/2.查询进阶/6.UNION/union.md

@@ -2,7 +2,7 @@
 
 现有员工信息表和顾客信息表如下
 
-```mysql
+```sql
 create table employee(
     id int primary key auto_increment,
     name varchar(256),
@@ -32,7 +32,7 @@ Joe 需要员工和顾客的联系方式（姓名+地址）清单，用于邮寄
 
 ## 答案
 
-```mysql
+```sql
 select name, address 
 from customer
 union
@@ -44,7 +44,7 @@ from employee
 
 ### A
 
-```mysql
+```sql
 select * 
 from customer
 union
@@ -54,7 +54,7 @@ from employee
 
 ### B
 
-```mysql
+```sql
 select * 
 from customer
 join employee
@@ -62,7 +62,7 @@ join employee
 
 ### C
 
-```mysql
+```sql
 select * 
 from customer
 join employee on customer.id = employee.id
@@ -70,14 +70,14 @@ join employee on customer.id = employee.id
 
 ### D
 
-```mysql
+```sql
 select * 
 from customer, employee
 ```
 
 ### E
 
-```mysql
+```sql
 select name, address 
 from customer, employee
 ```

data/2.MySQL中阶/2.查询进阶/7.正则表达式/regex.md

@@ -11,7 +11,7 @@ Joe 想要找出 goods 表中所有名称包含牛奶的冰激凌，他应该怎
 
 ## 答案
 
-```mysql
+```sql
 select * 
 from goods
 where name regexp '牛奶.*冰激凌';
@@ -21,7 +21,7 @@ where name regexp '牛奶.*冰激凌';
 
 ### A
 
-```mysql
+```sql
 select *
 from goods
 where name like '牛奶%冰激凌'
@@ -30,7 +30,7 @@ where name like '牛奶%冰激凌'
 
 ### B
 
-```mysql
+```sql
 select * 
 from goods
 where name like '牛奶.*冰激凌';
@@ -38,7 +38,7 @@ where name like '牛奶.*冰激凌';
 
 ### C
 
-```mysql
+```sql
 select * 
 from goods
 where name regexp '牛奶冰激凌';

data/2.MySQL中阶/2.查询进阶/8. 分页查询/paged.md

@@ -2,7 +2,7 @@
 
 我们有如下订单表：
 
-```mysql
+```sql
 create table orders
 (
     id          serial primary key,
@@ -24,7 +24,7 @@ create table orders
 
 ## 答案
 
-```mysql
+```sql
 select id, product_id, order_date, quantity, customer_id
 from orders
 where date = $1
@@ -35,7 +35,7 @@ offset $2 limit 100;
 
 ### 缺少 limit
 
-```mysql
+```sql
 select id, product_id, order_date, quantity, customer_id
 from orders
 where date = $1
@@ -44,7 +44,7 @@ offset $2;
 
 ### 缺少 offset
 
-```mysql
+```sql
 select id, product_id, order_date, quantity, customer_id
 from orders
 where date = $1; 
@@ -52,7 +52,7 @@ where date = $1;
 
 ### 结构不对
 
-```mysql
+```sql
 select id, product_id, order_date, quantity, customer_id
 from orders
 where date = $1 and

data/2.MySQL中阶/3.内置函数/5.其它函数/cast.md

@@ -11,7 +11,7 @@ Joe 想要把字符串表示的整数转为整数类型，可行的方法是：
 
 ## 答案
 
-```mysql
+```sql
 SELECT CAST('123' AS SIGNED);
 ```
 
@@ -19,7 +19,7 @@ SELECT CAST('123' AS SIGNED);
 
 ### A
 
-```mysql
+```sql
 select int('123');
 ```
 

data/2.MySQL中阶/3.内置函数/5.其它函数/convert.md

@@ -2,7 +2,7 @@
 
 Joe 需要将下面这个查询
 
-```mysql
+```sql
 select name from goods;
 ```
 
@@ -17,7 +17,7 @@ select name from goods;
 
 ##  答案
 
-```mysql
+```sql
 select convert(name using 'gb18030') from goods;
 ```
 
@@ -26,27 +26,27 @@ select convert(name using 'gb18030') from goods;
 
 ### A
 
-```mysql
+```sql
 select str(name, 'gb18303') from goods;
 ```
 
 
 ### B
 
-```mysql
+```sql
 select encode(decode(name, 'utf8mb4'), 'gb18303') from goods;
 ```
 
 
 ### C
 
-```mysql
+```sql
 select convert(name from 'utf8mb4' to 'gb18303') from goods;
 ```
 
 ### D
 
-```mysql
+```sql
 select convert(name to 'gb18303') from goods;
 ```
 

data/2.MySQL中阶/4.聚合和分组/1. 计数/count.md

@@ -16,7 +16,7 @@ mysql> select * from items;
 
 当他执行
 
-```mysql
+```sql
 select count(*), count(item) from items;
 ```
 

data/2.MySQL中阶/4.聚合和分组/2. 求和/sum.md

@@ -2,7 +2,7 @@
 
 Joe 想要得到 orders 表
 
-```mysql
+```sql
 create table orders (
                         id int primary key auto_increment,
                         item_id int,
@@ -26,7 +26,7 @@ create table orders (
 
 ## 答案
 
-```mysql
+```sql
 select sum(total) from orders where deal and unit_price > 1000;
 ```
 
@@ -34,24 +34,24 @@ select sum(total) from orders where deal and unit_price > 1000;
 
 ### A
 
-```mysql
+```sql
 select sum(total) from orders where deal and unit_price > 1000;
 ```
 
 ### B
 
-```mysql
+```sql
 select sum(total) from orders having deal and unit_price > 1000;
 ```
 
 ### C
 
-```mysql
+```sql
 select sum(total) from orders group by deal having unit_price > 1000;
 ```
 
 ### D
 
-```mysql
+```sql
 select sum(total) from orders having deal and unit_price > 1000;
 ```
\ No newline at end of file

data/2.MySQL中阶/4.聚合和分组/3.最小值/min.md

@@ -2,7 +2,7 @@
 
 Joe 想要得到 employee 表
 
-```mysql
+```sql
 create table employee
 (
     id     serial primary key,
@@ -23,7 +23,7 @@ create table employee
 
 ## 答案
 
-```mysql
+```sql
 select dept, min(salary) from employee group by dept;
 ```
 
@@ -31,24 +31,24 @@ select dept, min(salary) from employee group by dept;
 
 ### A
 
-```mysql
+```sql
 select dept, min(salary) from employee;
 ```
 
 ### B
 
-```mysql
+```sql
 select dept, min(salary) from employee;
 ```
 
 ### C
 
-```mysql
+```sql
 select dept, min(salary) from employee;
 ```
 
 ### D
 
-```mysql
+```sql
 select dept, min(total) from employee;
 ```
\ No newline at end of file

data/2.MySQL中阶/4.聚合和分组/4. 最大值/max.md

@@ -2,7 +2,7 @@
 
 利用员工信息表：
 
-```mysql
+```sql
 create table employee
 (
     id     serial primary key,
@@ -23,7 +23,7 @@ Joe 做了一些关于 max 函数的练习，其中不正确的是：
 
 ## 答案
 
-```mysql
+```sql
 select id, dept, max(salary) as salary, name 
 from employee
 group by dept
@@ -35,7 +35,7 @@ group by dept
 
 ### A
 
-```mysql
+```sql
 select dept, max(salary) as salary
 from employee
 group by dept
@@ -45,7 +45,7 @@ group by dept
 
 ### B
 
-```mysql
+```sql
 select max(salary) as salary
 from employee
 ```
@@ -54,7 +54,7 @@ from employee
 
 ### C
 
-```mysql
+```sql
 select dept, sum(salary)
 from employee
 group by dept
@@ -65,7 +65,7 @@ having max(salary) < 20000
 
 ### D
 
-```mysql
+```sql
 select dept, min(salary)
 from employee
 group by dept

data/2.MySQL中阶/4.聚合和分组/5. 平均值/avg.md

@@ -2,7 +2,7 @@
 
 Joe 想要得到 employee 表
 
-```mysql
+```sql
 create table employee
 (
     id     serial primary key,
@@ -23,7 +23,7 @@ create table employee
 
 ## 答案
 
-```mysql
+```sql
 select dept, avg(salary) from employee group by dept;
 ```
 
@@ -31,24 +31,24 @@ select dept, avg(salary) from employee group by dept;
 
 ### A
 
-```mysql
+```sql
 select dept, avg(salary) from employee;
 ```
 
 ### B
 
-```mysql
+```sql
 select dept, avg(salary) from employee;
 ```
 
 ### C
 
-```mysql
+```sql
 select dept, avg(salary) from employee;
 ```
 
 ### D
 
-```mysql
+```sql
 select dept, avg(salary) from employee ;
 ```
\ No newline at end of file

data/2.MySQL中阶/4.聚合和分组/6.HAVING/having.md

@@ -2,7 +2,7 @@
 
  Joe 要从 employee 表
  
-```mysql
+```sql
 create table employee
 (
     id     serial primary key,
@@ -23,7 +23,7 @@ create table employee
 
 ## 答案
 
-```mysql
+```sql
 select dept from employee group by dept having sum(salary) > 100000;
 ```
 
@@ -31,25 +31,25 @@ select dept from employee group by dept having sum(salary) > 100000;
 
 ### A
 
-```mysql
+```sql
 select dept from employee group by dept where sum(salary) > 100000;
 ```
 
 ### B
 
-```mysql
+```sql
 select dept from employee where sum(salary) > 100000 group by dept;
 ```
 
 ### C
 
-```mysql
+```sql
 select dept from employee where sum(salary) > 100000 order by dept;
 ```
 
 ### D
 
-```mysql
+```sql
 select dept from employee group by dept where sum(salary) > 100000;
 ```
 

data/2.MySQL中阶/5.子查询/1.相关子查询/subquery.md

@@ -2,7 +2,7 @@
 
 现有员工表
 
-```mysql
+```sql
 create table employee
 (
     id     serial primary key,
@@ -23,7 +23,7 @@ Joe 希望找出比销售部（dept 为 sale）工资最高的员工工资更高
 
 ## 答案
 
-```mysql
+```sql
 select id, name, dept, salary
 from employee
 where salary > (select max(salary)
@@ -35,7 +35,7 @@ where salary > (select max(salary)
 
 ### A
 
-```mysql
+```sql
 select id, name, dept, salary
 from employee
 where dept = 'sale'
@@ -45,7 +45,7 @@ having salary > max(salary)
 
 ### B
 
-```mysql
+```sql
 select l.id, l.name, l.dept, l.salary
 from employee as l
          join employee as r on l.salary > max(r.salary)
@@ -55,7 +55,7 @@ group by r.dept
 
 ### C
 
-```mysql
+```sql
 select id, name, dept, salary
 from employee
 having salary > (select max(salary) from employee where dept = 'sale')

data/2.MySQL中阶/5.子查询/2. ANY/any.md

@@ -2,7 +2,7 @@
 
 Joe 想要从员工表
 
-```mysql
+```sql
 create table employee(
     id int primary key auto_increment,
     name varchar(256),
@@ -22,7 +22,7 @@ create table employee(
 
 ## 答案
 
-```mysql
+```sql
 select id, name, dept, salary
 from employee as o
 where o.salary < any(select salary from employee as i where i.dept=o.dept)
@@ -32,7 +32,7 @@ where o.salary < any(select salary from employee as i where i.dept=o.dept)
 
 ### A
 
-```mysql
+```sql
 select id, name, dept, salary
 from employee as o
 join employee as i on o.dept = i.dept and o.salary < i.salary
@@ -40,7 +40,7 @@ join employee as i on o.dept = i.dept and o.salary < i.salary
 
 ### B
 
-```mysql
+```sql
 select o.id, o.name, o.dept, o.salary
 from employee as o
 left join employee as i on o.dept = i.dept and o.salary < i.salary
@@ -49,7 +49,7 @@ where i.id is null;
 
 ### C
 
-```mysql
+```sql
 select o.id, o.name, o.dept, o.salary 
 from employee as o 
     left join employee as i on o.dept = i.dept and o.salary < i.salary 

data/2.MySQL中阶/5.子查询/3.ALL/all.md

@@ -2,7 +2,7 @@
 
 Joe 想从员工表
 
-```mysql
+```sql
 create table employee(
     id int primary key auto_increment,
     dept_id int,
@@ -22,7 +22,7 @@ create table employee(
 
 ## 答案
 
-```mysql
+```sql
 select id, name, dept 
 from employee as o
 where 'assistant' != all(select post from employee as i where o.dept = i.dept); 
@@ -32,7 +32,7 @@ where 'assistant' != all(select post from employee as i where o.dept = i.dept);
 
 ### A
 
-```mysql
+```sql
 select id, name, dept 
 from employee as o
 where 'assistant' = all(select post from employee as i where o.dept = i.dept); 
@@ -40,14 +40,14 @@ where 'assistant' = all(select post from employee as i where o.dept = i.dept);
 
 ### B
 
-```mysql
+```sql
 select id, name, dept 
 from employee as o
 where 'assistant' != all(select post from employee as i where o.dept = i.dept); 
 ```
 
 ### C
-```mysql
+```sql
 select id, name, dept 
 from employee as o
 where 'assistant' != all(select post from employee as i); 
@@ -55,7 +55,7 @@ where 'assistant' != all(select post from employee as i);
 
 ### D
 
-```mysql
+```sql
 select id, name, dept 
 from employee as o
 where 'assistant' != ANY(select post from employee as i where o.dept = i.dept); 

data/2.MySQL中阶/5.子查询/4.EXISTS/exists.md

@@ -2,7 +2,7 @@
 
 Joe 想从员工表
 
-```mysql
+```sql
 create table employee(
     id int primary key auto_increment,
     dept_id int,
@@ -23,7 +23,7 @@ create table employee(
 
 ## 答案
 
-```mysql
+```sql
 select id, name, dept 
 from employee as o
 where not exists(select * from employee as i where o.dept = i.dept and post='assistant'); 
@@ -33,7 +33,7 @@ where not exists(select * from employee as i where o.dept = i.dept and post='ass
 
 ### A
 
-```mysql
+```sql
 select id, name, dept
 from employee as o
 where exists(select * from employee as i where o.dept = i.dept and post='assistant'); 
@@ -41,14 +41,14 @@ where exists(select * from employee as i where o.dept = i.dept and post='assista
 
 ### B
 
-```mysql
+```sql
 select id, name, dept
 from employee as o
 where not exists(select * from employee as i where o.dept = i.dept and post='assistant'); 
 ```
 
 ### C
-```mysql
+```sql
 select id, name, dept 
 from employee as o
 where 'assistant' != exists(select post from employee as i); 
@@ -56,7 +56,7 @@ where 'assistant' != exists(select post from employee as i);
 
 ### D
 
-```mysql
+```sql
 select id, name, dept 
 from employee as o
 where 'assistant' = not exists(select post from employee as i where o.dept = i.dept); 

data/2.MySQL中阶/5.子查询/5. IN/in.md

@@ -2,7 +2,7 @@
 
 Joe 想要从员工表
 
-```mysql
+```sql
 create table employee(
     id int primary key auto_increment,
     dept_id int,
@@ -22,7 +22,7 @@ create table employee(
 
 ## 答案
 
-```mysql
+```sql
 select id, dept, name, post 
 from employee
 where dept in ('dev', 'hr');
@@ -32,7 +32,7 @@ where dept in ('dev', 'hr');
 
 ### A
 
-```mysql
+```sql
 select id, dept, name, post 
 from employee
 where dept in (select 'dev', 'hr');
@@ -40,7 +40,7 @@ where dept in (select 'dev', 'hr');
 
 ### B
 
-```mysql
+```sql
 select id, dept, name, post 
 from employee
 where dept in (select * from 'dev', 'hr');
@@ -48,7 +48,7 @@ where dept in (select * from 'dev', 'hr');
 
 ### C
 
-```mysql
+```sql
 select id, dept, name, post 
 from employee
 where dept in ('dev' and 'hr');
@@ -56,7 +56,7 @@ where dept in ('dev' and 'hr');
 
 #### D
 
-```mysql
+```sql
 select id, dept, name, post 
 from employee
 where dept in ('dev' or 'hr');

data/2.MySQL中阶/5.子查询/6. 列子查询/in_column.md

@@ -2,7 +2,7 @@
 
 Joe 打算写一个查询，根据员工表
 
-```mysql
+```sql
 create table employee
 (
     id   int primary key auto_increment,
@@ -23,7 +23,7 @@ create table employee
 
 ## 答案
 
-```mysql
+```sql
 select distinct(dept)                  as dept,
                (select count(*)
                 from employee as i
@@ -35,7 +35,7 @@ from employee as o;
 
 ### A
 
-```mysql
+```sql
 select distinct(dept)               as dept,
                (select count(*)
                 from employee as i) as emp
@@ -44,7 +44,7 @@ from employee as o;
 
 ### B
 
-```mysql
+```sql
 select distinct(dept)              as dept,
                (select count(*)
                 from employee
@@ -54,7 +54,7 @@ from employee
 
 ### C
 
-```mysql
+```sql
 select dept                    as dept,
        (select count(*)
         from employee as i

data/2.MySQL中阶/6.连接查询/1.INNER JOIN/join_self.md

@@ -2,7 +2,7 @@
 
 现有 node 表如下：
 
-```mysql
+```sql
 create table node(
     id int primary key auto_increment,
     pid int,
@@ -22,7 +22,7 @@ create table node(
 
 ## 答案
 
-```mysql
+```sql
 select l.id as parent_id, 
        l.content as parent_content,
        r.id as child_id,
@@ -36,7 +36,7 @@ where l.content like 'fork-%';
 
 ### A
 
-```mysql
+```sql
 select l.id as parent_id, 
        l.content as parent_content,
        r.id as child_id,
@@ -48,7 +48,7 @@ where l.content like 'fork-%';
 
 ### B
 
-```mysql
+```sql
 select l.id as parent_id, 
        l.content as parent_content,
        r.id as child_id,
@@ -59,7 +59,7 @@ where l.id =(+) r.pid l.content like 'fork-%';
 
 ### C
 
-```mysql
+```sql
 select l.id as parent_id, 
        l.content as parent_content,
        r.id as child_id,
@@ -71,7 +71,7 @@ where l.content like 'fork-%';
 
 ### D
 
-```mysql
+```sql
 select l.id as parent_id, 
        l.content as parent_content,
        r.id as child_id,

data/2.MySQL中阶/6.连接查询/2. LEFT JOIN/left_join.md

@@ -2,7 +2,7 @@
 
 现有部门表
 
-```mysql
+```sql
 create table department(
     id int primary key auto_increment,
     name varchar(256)
@@ -11,7 +11,7 @@ create table department(
 
 和员工表
 
-```mysql
+```sql
 create table employee(
     id int primary key auto_increment,
     dept_id int,
@@ -31,7 +31,7 @@ Joe 想要列出所有的部门，如果这个部门有部门助理（post 为 `
 
 ## 答案
 
-```mysql
+```sql
 select d.id, d.name, e.name as assistant
 from department as d
     left join employee as e on e.dept = d.id
@@ -42,7 +42,7 @@ where e.post = 'assistant'
 
 ### A
 
-```mysql
+```sql
 select d.id, d.name, e.name as assistant
 from department as d
          cross join employee as e on e.dept = d.id
@@ -51,7 +51,7 @@ where e.post = 'assistant'
 
 ### B
 
-```mysql
+```sql
 select d.id, d.name, e.name as assistant
 from department as d
          join employee as e on e.dept = d.id
@@ -60,7 +60,7 @@ where e.post = 'assistant'
 
 ### C
 
-```mysql
+```sql
 select d.id, d.name, e.name as assistant
 from department as d
          cross join employee as e on e.dept = d.id
@@ -69,7 +69,7 @@ where e.post = 'assistant'
  
 ### D
 
-```mysql
+```sql
 select d.id, d.name, e.name as assistant
 from employee as e
     left join department as d on e.dept = d.id

data/2.MySQL中阶/6.连接查询/3. RIGHT JOIN/right_join.md

@@ -2,7 +2,7 @@
 
 现有部门表
 
-```mysql
+```sql
 create table department(
     id int primary key auto_increment,
     name varchar(256)
@@ -11,7 +11,7 @@ create table department(
 
 和员工表
 
-```mysql
+```sql
 create table employee(
     id int primary key auto_increment,
     dept_id int,
@@ -32,7 +32,7 @@ create table employee(
 
 ## 答案
 
-```mysql
+```sql
 select e.id, e.name, e.dept
 from department as d
     right join employee as e on d.id = e.dept
@@ -43,7 +43,7 @@ where d.id is null;
 
 ### A
 
-```mysql
+```sql
 select e.id, e.name, e.dept
 from employee as e
          right join department as d on d.id = e.dept
@@ -52,7 +52,7 @@ where e.id is null;
 
 ### B
 
-```mysql
+```sql
 select e.id, e.name, e.dept
 from employee as e
          right join department as d on d.id = e.dept
@@ -61,7 +61,7 @@ where d.id is null;
 
 ### C
 
-```mysql
+```sql
 select e.id, e.name, e.dept
 from department as d
     join employee as e on d.id = e.dept
@@ -71,7 +71,7 @@ where d.id is null;
 
 ### D
 
-```mysql
+```sql
 select e.id, e.name, e.dept
 from department as d
     right join employee as e on d.id = e.dept

data/2.MySQL中阶/6.连接查询/4. CROSS JOIN/cross_join.md

@@ -2,7 +2,7 @@
 
 Joe 需要生成 goods 表
 
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category varchar(64),
@@ -15,7 +15,7 @@ create table goods(
 
 中所有T恤（category为`T-Shirt`）的所有尺寸，尺寸信息在 size 表
 
-```mysql
+```sql
 create table size(
     id int primary key auto_increment,
     name varchar(16)
@@ -33,7 +33,7 @@ create table size(
 
 ## 答案
 
-```mysql
+```sql
 select g.id, g.name, s.name as size
 from goods as g
     cross join size as s
@@ -44,7 +44,7 @@ where g.category = 'T-Shirt';
 
 ### A
 
-```mysql
+```sql
 select g.id, g.name, s.name as size
 from goods as g
     full join size as s
@@ -53,7 +53,7 @@ where g.category = 'T-Shirt';
 
 ### B
 
-```mysql
+```sql
 select g.id, g.name, s.name as size
 from goods as g
     left join size as s
@@ -62,7 +62,7 @@ where g.category = 'T-Shirt';
 
 ### C
 
-```mysql
+```sql
 select g.id, g.name, s.name as size
 from goods as g
     left join size as s
@@ -71,7 +71,7 @@ where g.category = 'T-Shirt';
 
 ### D
 
-```mysql
+```sql
 select g.id, g.name, s.name as size
 from goods as g
     right join size as s
@@ -80,7 +80,7 @@ where g.category = 'T-Shirt';
 
 ### E
 
-```mysql
+```sql
 select g.id, g.name, s.name as size
 from goods as g
     outter join size as s

data/2.MySQL中阶/6.连接查询/5. 复杂连接/salary.md

@@ -2,7 +2,7 @@
 
 现有员工信息表如下：
 
-```mysql
+```sql
 create table employee
 (
     id     serial primary key,
@@ -23,7 +23,7 @@ create table employee
 
 ## 答案
 
-```mysql
+```sql
 select l.id, l.name, l.dept, l.salary
 from employee as l
          join (select max(salary) as salary, dept
@@ -36,7 +36,7 @@ from employee as l
 
 ### select 与 group by 不匹配
 
-```mysql
+```sql
 select id, name, dept, max(salary)
 from employee
 group by dept;
@@ -44,7 +44,7 @@ group by dept;
 
 ### group by 不对
 
-```mysql
+```sql
 select id, name, dept, max(salary)
 from employee
 group by dept, id, name;
@@ -52,7 +52,7 @@ group by dept, id, name;
 
 ### group by 不对
 
-```mysql
+```sql
 select id, name, dept, max(salary)
 from employee
 group by dept, id, name
@@ -61,7 +61,7 @@ having salary = max(salary);
 
 ### 结构错误
 
-```mysql
+```sql
 select id, name, dept, max(salary)
 from employee
 where salary = max(salary)

data/2.MySQL中阶/7. 索引/2.创建索引/create_index.md

@@ -2,7 +2,7 @@
 
 Joe 想给 Goods 表
 
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category_id int,
@@ -26,7 +26,7 @@ create table goods(
 
 ## 答案
 
-```mysql
+```sql
 create index idx_goods_category on goods(category_id);
 ```
 
@@ -34,18 +34,18 @@ create index idx_goods_category on goods(category_id);
 
 ### A
 
-```mysql
+```sql
 create unique index idx_goods_category on goods(category_id);
 ```
 
 ### B
 
-```mysql
+```sql
 create index idx_goods_category on goods(category_id);
 ```
 
 ### C
 
-```mysql
+```sql
 alter table goods add unique index (category_id);
 ```
\ No newline at end of file

data/2.MySQL中阶/7. 索引/3.删除索引/drop_index.md

@@ -13,13 +13,13 @@ Joe 想要删除创建在 goods 表创建的索引，但是他已经忘了这个
 
 执行
 
-```mysql
+```sql
 show index from goods;
 ```
 
 查看 goods 表的索引（假设查到是 idx_goods_category），然后执行
 
-```mysql
+```sql
 alter table goods drop index idx_goods_category;
 ```
 
@@ -29,13 +29,13 @@ alter table goods drop index idx_goods_category;
 
 执行
 
-```mysql
+```sql
 show index from goods;
 ```
 
 查看 goods 表的索引（假设查到是 idx_goods_category），然后执行
 
-```mysql
+```sql
 alter table goods delete index idx_goods_category;
 ```
 
@@ -43,13 +43,13 @@ alter table goods delete index idx_goods_category;
 
 执行
 
-```mysql
+```sql
 show index from goods;
 ```
 
 查看 goods 表的索引（假设查到是 idx_goods_category），然后执行
 
-```mysql
+```sql
 alter table goods remove index idx_goods_category;
 ```
 
@@ -57,13 +57,13 @@ alter table goods remove index idx_goods_category;
 
 执行
 
-```mysql
+```sql
 show index from goods;
 ```
 
 查看 goods 表的索引（假设查到是 idx_goods_category），然后执行
 
-```mysql
+```sql
 alter table goods drop idx_goods_category;
 ```
 

data/3.MySQL高阶/1.深入索引/1.唯一索引/unique.md

@@ -2,7 +2,7 @@
 
 Goods 表结构如下：
 
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category_id int,
@@ -24,7 +24,7 @@ Joe 需要确保同一个类型下没有重名的商品，他应该怎么做？
 
 ## 答案
 
-```mysql
+```sql
 alter table goods add unique index (category_id, name);
 ```
 
@@ -32,18 +32,18 @@ alter table goods add unique index (category_id, name);
 
 ### A
 
-```mysql
+```sql
 alter table goods add index (category_id, name);
 ```
 
 ### B
 
-```mysql
+```sql
 alter table goods add unique index (category_id + name);
 ```
 
 ### C
 
-```mysql
+```sql
 alter table goods add unique index (concat(category_id, name));
 ```

data/3.MySQL高阶/1.深入索引/2.全值匹配/total_index.md

@@ -2,7 +2,7 @@
 
 Goods 表结构如下：
 
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category_id int,
@@ -24,7 +24,7 @@ create table goods(
 
 ## 答案
 
-```mysql
+```sql
 alter table goods add index (name, price);
 ```
 
@@ -38,12 +38,12 @@ alter table goods add index (name, price);
 
 建立一个计算字段：
 
-```mysql
+```sql
 alter table goods add summary varchar(1024) generated always as (concat(name, '(', 0.5, ')'));
 ```
 
 ### C
 
-```mysql
+```sql
 alter table goods add index (concat(name, price));
 ```
\ No newline at end of file

data/3.MySQL高阶/1.深入索引/3.匹配顺序/match_fields.md

@@ -2,7 +2,7 @@
 
 Goods 表结构如下：
 
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category_id int,
@@ -28,7 +28,7 @@ Joe 发现有大量查询 `select id, category_id, name, price from goods where
 
 将该查询改写为 
 
-```mysql
+```sql
 select id, category_id, name, price from goods where category_id=? and name=?;
 ```
 
@@ -38,7 +38,7 @@ select id, category_id, name, price from goods where category_id=? and name=?;
 
 将该查询改写为
 
-```mysql
+```sql
 select id, category_id, name, price from goods where category_id and name= (?, ?);
 ```
 
@@ -46,7 +46,7 @@ select id, category_id, name, price from goods where category_id and name= (?, ?
 
 将该查询改写为
 
-```mysql
+```sql
 select id, category_id, name, price from goods where not (category_id !=? or name != ?);
 ```
 
@@ -54,7 +54,7 @@ select id, category_id, name, price from goods where not (category_id !=? or nam
 
 将该查询改写为
 
-```mysql
+```sql
 select id, category_id, name, price from goods where not (category_id !=?) and not (name != ?);
 ```
 

data/3.MySQL高阶/1.深入索引/4.组合索引/combinate.md

@@ -2,7 +2,7 @@
 
 Goods 表结构如下：
 
-```mysql
+```sql
 create table goods(
     id int primary key auto_increment,
     category_id int,
@@ -26,7 +26,7 @@ Joe 应该如何优化？
 
 ## 答案
 
-```mysql
+```sql
 alter table goods add index (`stock-id`, category_id, name);
 ```
 
@@ -34,18 +34,18 @@ alter table goods add index (`stock-id`, category_id, name);
 
 ### A
 
-```mysql
+```sql
 alter table goods add index (`stock-id` and category_id and name);
 ```
 
 ### B
 
-```mysql
+```sql
 alter table goods add index (concat(stock, category_id, name));
 ```
 
 ### C
 
-```mysql
+```sql
 alter table goods add index (`stock-id` + category_id + name);
 ```

data/3.MySQL高阶/1.深入索引/5.空间索引/geo_index.md

@@ -2,7 +2,7 @@
 
 Goods 数据库中有一个 shop 表，其中包含如下字段：
 
-```mysql
+```sql
 create table shop (
     id int primary key auto_increment,
     location GEOMETRY
@@ -21,7 +21,7 @@ create table shop (
 
 ## 答案
 
-```mysql
+```sql
 alter table shop modify location  GEOMETRY not null;
 alter table shop add INDEX geo_index(location);
 ```
@@ -30,26 +30,26 @@ alter table shop add INDEX geo_index(location);
 
 ### A
 
-```mysql
+```sql
 alter table shop add INDEX geo_index(location);
 ```
 
 ### B
 
-```mysql
+```sql
 alter table shop add INDEX location;
 ```
 
 ### C
 
-```mysql
+```sql
 alter table shop modify location  GEOMETRY not null;
 alter table shop add INDEX location;
 ```
 
 ### D
 
-```mysql
+```sql
 alter table shop modify location  GEOMETRY not null;
 alter table shop add INDEX location;
 ```

data/3.MySQL高阶/1.深入索引/6.全文索引/full_text_index.md

@@ -2,7 +2,7 @@
 
 Shop 表的部分字段如下：
 
-```mysql
+```sql
 create table shop (
     id int primary key auto_increment,
     description varchar(8000)
@@ -21,7 +21,7 @@ create table shop (
 
 ## 答案
 
-```mysql
+```sql
 alter table shop add fulltext(description);
 ```
 
@@ -29,18 +29,18 @@ alter table shop add fulltext(description);
 
 ### A
 
-```mysql
+```sql
 alter table shop add index fulltext(description);
 ```
 
 ### B
 
-```mysql
+```sql
 alter table shop create fulltext(description);
 ```
 
 ### C
 
-```mysql
+```sql
 alter table shop alter description add fulltext(description);
 ```
\ No newline at end of file

data/3.MySQL高阶/1.深入索引/7.隐藏索引/invisible.md

@@ -2,7 +2,7 @@
 
 Shop 表的部分字段如下：
 
-```mysql
+```sql
 create table shop (
     id int primary key auto_increment,
     description varchar(8000),
@@ -27,13 +27,13 @@ Joe 应该怎么做？
 
 先执行
 
-```mysql
+```sql
 alter table shop alter index description invisible ;
 ```
 
 将索引隐藏，观察确认没有影响后再执行
 
-```mysql
+```sql
 alter table shop drop index description;
 ```
 
@@ -46,7 +46,7 @@ alter table shop drop index description;
 
 先备份 shop 表，然后执行
 
-```mysql
+```sql
 alter table shop drop index description;
 ```
 删除，有问题的话从备份文件恢复。
@@ -59,13 +59,13 @@ alter table shop drop index description;
 
 先执行
 
-```mysql
+```sql
 alter table shop alter index description invisible ;
 ```
 
 将索引隐藏，确认后再执行
 
-```mysql
+```sql
 alter table shop alter index description visible ;
 ```
 

data/3.MySQL高阶/1.深入索引/8.函数和表达式索引/daily_payment.md

@@ -2,7 +2,7 @@
 
 数据分析组需要经常执行以下查询生成从昨天到之前某一天的交易量统计
 
-```mysql
+```sql
 select date(payment_date) as day, sum(amount)
 from payment
 where date(payment_date) between $1 and DATE_SUB(CURDATE(), INTERVAL 1 DAY)
@@ -39,7 +39,7 @@ mysql> desc payment;
 
 建立表达式索引
 
-```mysql
+```sql
 alter table payment add index idx_payment_date((date(payment_date)));
 ```
 
@@ -49,13 +49,13 @@ alter table payment add index idx_payment_date((date(payment_date)));
 
 建立视图
 
-```mysql
+```sql
 create view view_daily_payment as select date(payment_date) as day, amount from payment;
 ```
 
 然后在视图 view_daily_payment 上执行
 
-```mysql
+```sql
 select day, sum(amount) 
 from view_daily_payment
 where day between $1 and DATE_SUB(CURDATE(), INTERVAL 1 DAY)
@@ -66,7 +66,7 @@ group by day
 
 在 payment_date 列上建立索引
 
-```mysql
+```sql
 create index idx_payment_date on payment(payment_date);
 ```
 
@@ -74,13 +74,13 @@ create index idx_payment_date on payment(payment_date);
 
 建立计算列
 
-```mysql
+```sql
 alter table payment add day date generated always as (date(payment_date)) stored; 
 ```
 
 然后使用它改写查询
 
-```mysql
+```sql
 select day as day, sum(amount)
 from payment
 where day between $1 and date('yesterday')

data/3.MySQL高阶/2.SQL高级技巧/1.CTE和递归查询/continuous.md

@@ -3,7 +3,7 @@
 SmartMarket 交易所的系统中，所有订单在生成时，都从一个 oracle Sequence 中获取唯一的 
 序列号，完成交易计算后各个撮合程序将其插入如下的 orders 表中：
 
-```mysql
+```sql
 create table orders
 (
     id      integer primary key,
@@ -27,7 +27,7 @@ create table orders
 
 ## 答案
 
-```mysql
+```sql
 with recursive r(id) as (select id
                          from orders
                          where id = $1
@@ -48,7 +48,7 @@ from orders
 
 ### B
 
-```mysql
+```sql
 select data.id, content
 from orders
          join orders as r on orders.id = r.id - 1
@@ -57,7 +57,7 @@ where id = $1;
 
 ### C
 
-```mysql
+```sql
 select id, content
 from orders
 where id in (select id from orders where id = id + 1);
@@ -65,7 +65,7 @@ where id in (select id from orders where id = id + 1);
 
 ### D
 
-```mysql
+```sql
 with r as (select id
            from orders
            where id = $1

data/3.MySQL高阶/2.SQL高级技巧/1.CTE和递归查询/to_root.md

@@ -2,7 +2,7 @@
 
 现有一个表 node
 
-```mysql
+```sql
 create table node
 (
     id      int primary key auto_increment,
@@ -24,7 +24,7 @@ create table node
 
 ## 答案
 
-```mysql
+```sql
 with recursive t(id, pid, val) as (
     select id, pid, val
     from node
@@ -42,7 +42,7 @@ from node
 
 ### 没有递归定义
 
-```mysql
+```sql
 with t as (
     select id, pid, val
     from node
@@ -58,7 +58,7 @@ from node
 
 ### 平凡的连接查询无法处理递归问题
 
-```mysql
+```sql
 select node.id, node.pid, node.val
 from node
          join node as p on node.pid = p.id
@@ -67,7 +67,7 @@ where id = $1;
 
 ### 子查询无法处理递归问题
 
-```mysql
+```sql
 select node.id, node.pid, node val
 from node as t
 where t.pid = (select id from t where id = t.pid)

data/3.MySQL高阶/2.SQL高级技巧/2.Window Function/salary.md

@@ -2,7 +2,7 @@
 
 现有员工信息表如下：
 
-```mysql
+```sql
 create table employee
 (
     id     serial primary key,
@@ -23,7 +23,7 @@ create table employee
 
 ## 答案
 
-```mysql
+```sql
 select id, name, dept, salary
 from (select id, name, dept, salary, rank() over (partition by dept order by salary desc) as r
       from employee) as t
@@ -34,7 +34,7 @@ where r <= 5;
 
 ### 结构错误
 
-```mysql
+```sql
 select id, name, dept, max(salary) as salary
 from employee
 group by dept
@@ -43,7 +43,7 @@ having id < 6;
 
 ### 结构错误
 
-```mysql
+```sql
 select l.id, l.name, l.dept, l.salary
 from employee as l
          join (select max(salary) as salary, dept
@@ -55,7 +55,7 @@ where count(r.id) <= 5;
 
 ### 结构错误
 
-```mysql
+```sql
 select l.id, l.name, l.dept, l.salary
 from employee as l
          join (select max(salary, 5) as salary, dept
@@ -66,7 +66,7 @@ from employee as l
 
 ### 结构错误
 
-```mysql
+```sql
 select id, name, dept, salary, rank() over (partition by dept order by salary desc) as r
 from employee
 where r <= 5;
@@ -74,7 +74,7 @@ where r <= 5;
 
 ### 结构错误
 
-```mysql
+```sql
 select id, name, dept, salary, rank() as r over (partition by dept order by salary desc)
 from employee
 where r <= 5;

data/3.MySQL高阶/2.SQL高级技巧/3.透视表 /pivot.md

@@ -2,7 +2,7 @@
 
 现有销售记录表
 
-```mysql
+```sql
 create table sales(
     id serial primary key ,
     sku_id integer not null ,
@@ -23,7 +23,7 @@ create index on sales(created_at);
 
 ## 答案
 
-```mysql
+```sql
 select sku_id, 
        sum(case extract(month from created_at) when 1 then amount else 0 end) as Jan,
        sum(case extract(month from created_at) when 2 then amount else 0 end) as Feb,
@@ -46,7 +46,7 @@ group by sku_id;
 
 ### 格式不相符
 
-```mysql
+```sql
 select sku_id, extract(month from created_at) as month, sum(amount) 
 from sales
 where created_at between '2020-01-01'::timestamp and '2021-01-01'::timestamp
@@ -55,7 +55,7 @@ group by 1, 2;
 
 ### 计算逻辑错误
 
-```mysql
+```sql
 select sku_id, 
        sum(amount) as Jan,
        sum(amount) as Feb,
@@ -76,7 +76,7 @@ group by sku_id, extract(month from created_at);
 
 ### 计算格式错误
 
-```mysql
+```sql
 select sku_id, 
        sum(amount having extract(month from created_at) = 1) as Jan,
        sum(amount having extract(month from created_at) = 2) as Feb,

data/3.MySQL高阶/2.SQL高级技巧/4.Double Not Exists/DoubleNotExists.md

@@ -2,7 +2,7 @@
 
 风控部门的数据库中有一组关于招投标的数据，关键信息如下：
 
-```mysql
+```sql
 -- 招标项目
 create table invitation
 (
@@ -42,7 +42,7 @@ Joe 想要找出参与了所有投标的企业（有围标嫌疑），那么这
 
 ## 答案
 
-```mysql
+```sql
 select *
 from company
 where not exists(
@@ -61,7 +61,7 @@ where not exists(
 
 ### A
 
-```mysql
+```sql
 select *
 from company
 where id = all (select company_id
@@ -70,7 +70,7 @@ where id = all (select company_id
 
 ### B
 
-```mysql
+```sql
 select *
 from company
 where id = any (select company_id
@@ -79,7 +79,7 @@ where id = any (select company_id
 
 ### C
 
-```mysql
+```sql
 select *
 from company
 where company.id in (select distinct company_id from bids) 
@@ -87,7 +87,7 @@ where company.id in (select distinct company_id from bids)
 
 ### D
 
-```mysql
+```sql
 select *
 from company
 where exists(

data/3.MySQL高阶/2.SQL高级技巧/5.写入和冲突/score.md

@@ -2,7 +2,7 @@
 
 现有一个表
 
-```mysql
+```sql
 create table book_in(
     login integer primary key ,
     score integer default 0
@@ -21,7 +21,7 @@ create table book_in(
 
 ## 答案
 
-```mysql
+```sql
 insert into book_in(login, score) values ($1, $2) on DUPLICATE KEY update score=$2;
 ```
 
@@ -29,7 +29,7 @@ insert into book_in(login, score) values ($1, $2) on DUPLICATE KEY update score=
 
 ### A
 
-```mysql
+```sql
 try
     insert into book_in(login, score) values ($1, $2);
 catch
@@ -40,18 +40,18 @@ finally
 
 ### B
 
-```mysql
+```sql
 insert into book_in(login, score) select $1, $2;
 ```
 
 ### C
 
-```mysql
+```sql
 replace book_in(login, score) select $1, $2;
 ```
 
 ### D
 
-```mysql
+```sql
 upsert into book_in(login, score) select $1, $2;
 ```

data/3.MySQL高阶/2.SQL高级技巧/6.事务/transaction.md

@@ -2,13 +2,13 @@
 
 现有 test1 表如下
 
-```mysql
+```sql
 create table test1(a integer primary key );
 ```
 
 我们执行下面的语句
 
-```mysql
+```sql
 CREATE PROCEDURE transaction_test1()
 BEGIN
     declare idx int;

data/3.MySQL高阶/3. 过程化编程/1.IF/if.md

@@ -17,7 +17,7 @@ Goods 数据库中有一个名为 trade 的存储过程，封装了交易过程
 
 ## 答案
 
-```mysql
+```sql
 set @counter = @counter + 1;
 if @counter % 1000 = 0 then
     set @total_price = @total_price * 0.8;
@@ -28,7 +28,7 @@ end if;
 
 ### A
 
-```mysql
+```sql
 set @counter = @counter + 1;
 if @counter % 1000 = 0 {
     set @total_price = @total_price * 0.8;
@@ -37,7 +37,7 @@ if @counter % 1000 = 0 {
 
 ### B
 
-```mysql
+```sql
 set @counter = @counter + 1;
 if (@counter % 1000 = 0) {
     set @total_price = @total_price * 0.8;
@@ -46,7 +46,7 @@ if (@counter % 1000 = 0) {
 
 ### C
 
-```mysql
+```sql
 if @counter % 1000 = 0 begin ;
     set @total_price = @total_price * 0.8;
 end;
@@ -54,7 +54,7 @@ end;
 
 ### D
 
-```mysql
+```sql
 set @counter ++;
 if @counter % 1000 = 0 then begin 
     select @total_price = @total_price * 0.8;

data/3.MySQL高阶/3. 过程化编程/2.LOOP/loop.md

@@ -13,7 +13,7 @@
 
 ## 答案
 
-```mysql
+```sql
 -- ...
 trade: LOOP
     if @price > 1000 then
@@ -33,7 +33,7 @@ end LOOP trace;
 
 ### A
 
-```mysql
+```sql
 -- ...
 trade: LOOP
     if @price > 1000 then
@@ -49,7 +49,7 @@ end LOOP trace;
 
 ### B
 
-```mysql
+```sql
 -- ...
 trade: LOOP
     if @price > 1000 then
@@ -67,7 +67,7 @@ end LOOP trace;
 
 ### C
 
-```mysql
+```sql
 -- ...
 trade: LOOP
     if @price > 1000 then
@@ -85,7 +85,7 @@ end LOOP trace;
 
 ### D
 
-```mysql
+```sql
 -- ...
 trade: LOOP
     if @price > 1000 then

data/3.MySQL高阶/3. 过程化编程/3.REPEAT/repeat.md

@@ -2,7 +2,7 @@
 
 交易过程 trade 中有一个遍历交易项的循环，当累计的总交易额 `@total_price` 超过 20000， 这个循环就结束
 
-```mysql
+```sql
 -- ...
 trade: LOOP
     -- ... 
@@ -26,7 +26,7 @@ end LOOP trace;
 
 ## 答案
 
-```mysql
+```sql
 trade: REPEATE
     -- 省略交易过程
     UNTIL @total_price > 20000
@@ -37,7 +37,7 @@ END REPATE trade;
 
 ### A
 
-```mysql
+```sql
 trade: REPEATE
     UNTIL @total_price > 20000
     -- 省略交易过程
@@ -46,7 +46,7 @@ END REPATE trade;
 
 ### B
 
-```mysql
+```sql
 REPEATE @total_price > 20000
     -- 省略交易过程
 END REPATE;
@@ -54,7 +54,7 @@ END REPATE;
 
 ### C
 
-```mysql
+```sql
 trade: REPEATE
     -- 省略交易过程
     IF @total_price > 20000
@@ -63,7 +63,7 @@ END REPATE trade;
 
 ### D
 
-```mysql
+```sql
 trade: REPEATE
     IF @total_price > 20000
     -- 省略交易过程

data/3.MySQL高阶/3. 过程化编程/4.WHILE/while.md

@@ -2,7 +2,7 @@
 
 交易过程 trade 中有一个遍历交易项的循环，当累计的总交易额 `@total_price` 超过 20000， 这个循环就结束
 
-```mysql
+```sql
 -- ...
 trade: LOOP
     -- ... 
@@ -26,7 +26,7 @@ end LOOP trace;
 
 ## 答案
 
-```mysql
+```sql
 trade: WHILE @total_price > 20000
     -- 省略交易过程
 END WHILE trade;
@@ -36,7 +36,7 @@ END WHILE trade;
 
 ### A
 
-```mysql
+```sql
 trade: DO 
     -- 省略交易过程
 WHILE @total_price > 20000;
@@ -44,7 +44,7 @@ WHILE @total_price > 20000;
 
 ### B
 
-```mysql
+```sql
 trade: WHILE @total_price > 20000
     -- 省略交易过程
 END WHILE trade;
@@ -52,7 +52,7 @@ END WHILE trade;
 
 ### C
 
-```mysql
+```sql
 trade: WHILE @total_price > 20000 DO
     -- 省略交易过程
 END WHILE trade;
@@ -60,7 +60,7 @@ END WHILE trade;
 
 ### D
 
-```mysql
+```sql
 trade: WHILE @total_price > 20000
     -- 省略交易过程
 END WHILE;

data/3.MySQL高阶/3. 过程化编程/5. 游标/cursor.md

@@ -2,7 +2,7 @@
 
 Joe 需要开发一个存储过程 make_trade，从 orders 表
 
-```mysql
+```sql
 create table orders (
     id int primary key auto_increment,
     price decimal(12, 4),
@@ -13,7 +13,7 @@ create table orders (
 
 中，按 id 从小到大加载订单数据，生成交易单，写入 trade 表 
 
-```mysql
+```sql
 create table trade (
     id int primary key auto_increment,
     total decimal(12, 4)
@@ -36,7 +36,7 @@ create table trade (
 
 ## 答案
 
-```mysql
+```sql
 create procedure make_trade()
 begin
     DECLARE done INT DEFAULT FALSE;
@@ -70,7 +70,7 @@ end;
 
 ### A
 
-```mysql
+```sql
 create procedure make_trade()
 begin
     DECLARE done INT DEFAULT FALSE;
@@ -97,7 +97,7 @@ end;
 
 ### B
 
-```mysql
+```sql
 create procedure make_trade()
 begin
     declare cur_orders cursor for select id, price, item_id, amount from orders order by id limit 1000;
@@ -118,7 +118,7 @@ end;
 
 ### C
 
-```mysql
+```sql
 create procedure make_trade()
 begin
     DECLARE done INT DEFAULT FALSE;
@@ -139,7 +139,7 @@ end;
 
 ### D
 
-```mysql
+```sql
 create procedure make_trade()
 begin
     DECLARE done INT DEFAULT FALSE;

data/3.MySQL高阶/4.设计优化/1.生成列/generated.md

@@ -2,7 +2,7 @@
 
 Joe 需要为 Points 表
 
-```mysql
+```sql
 create table points(
     id int primary key auto_increment,
     x float,
@@ -21,7 +21,7 @@ create table points(
 
 ## 答案
 
-```mysql
+```sql
 alter table points add modulus double generated always as (sqrt(x*x + y*y));
 ```
 
@@ -29,18 +29,18 @@ alter table points add modulus double generated always as (sqrt(x*x + y*y));
 
 ### A
 
-```mysql
+```sql
 create generated modulus on table points as (sqrt(x*x + y*y));
 ```
 
 ### B
 
-```mysql
+```sql
 alter table points add modulus generated always as (sqrt(x*x + y*y));
 ```
 
 ### C
 
-```mysql
+```sql
 alter table points add modulus float generated sqrt(x*x + y*y);
 ```

data/3.MySQL高阶/4.设计优化/2. 范式设计/customer_order.md

@@ -2,7 +2,7 @@
 
 Goods 中有客户/订单系统如下：
 
-```mysql
+```sql
 create table customers
 (
     id           serial primary key,

data/3.MySQL高阶/4.设计优化/4.增加中间表/daily_payment2.md

@@ -3,7 +3,7 @@
 # 每日报表
 
 分析过去一段时间的查询数据，Joe 发现 payment 表
-```mysql
+```sql
 create table payment(
     payment_id int primary key auto_increment,
     customer_id int,
@@ -16,7 +16,7 @@ create table payment(
 每天的订单量很大，下面这个查询的统计过程占用了大多数数据库资源，查询不会
 早于当天，总是在历史上某一个日期段内查询
 
-```mysql
+```sql
 select date(payment_date) as day, sum(amount)
 from payment
 where date(payment_date) between $1 and $2
@@ -47,13 +47,13 @@ select payment_date::date as day, sum(amount) as amount from payment group by da
 
 使用
 
-```mysql
+```sql
 select day, amount from view_daily_payment where day between $1 and $2;
 ```
 
 进行查询。并且每天定时执行一次刷新命令
 
-```mysql
+```sql
 insert into daily_payment(day, amount)
 select date(payment_date) as day, sum(amount) as amount 
 from payment
@@ -68,7 +68,7 @@ group by day;
 
 在 payment_date 列上建立索引
 
-```mysql
+```sql
 create index idx_payment_date on payment(payment_date);
 ```
 
@@ -76,13 +76,13 @@ create index idx_payment_date on payment(payment_date);
 
 建立计算列
 
-```mysql
+```sql
 alter table payment add day date generated always as ( payment_date::date ) stored 
 ```
 
 然后使用它改写查询
 
-```mysql
+```sql
 select day as day, sum(amount)
 from payment
 where day between $1 and DATE_SUB(CURDATE(), INTERVAL 1 DAY)
@@ -93,7 +93,7 @@ group by day;
 
 建立表达式索引
 
-```mysql
+```sql
 create index idx_payment_day on payment((date(payment_date)));
 ```
 
@@ -101,13 +101,13 @@ create index idx_payment_day on payment((date(payment_date)));
 
 建立视图
 
-```mysql
+```sql
 create view view_daily_payment as select date(payment_date) as day, amount from payment;
 ```
 
 然后在视图 view_daily_payment 上执行
 
-```mysql
+```sql
 select day, sum(amount) 
 from view_daily_payment
 where day between $1 and date('yesterday')

data/3.MySQL高阶/5.运维与架构/6.复制过滤器/filter.md

@@ -19,7 +19,7 @@
 
 可以在主库中执行以下命令设定只复制 goods 数据库和 auth 数据库
 
-```mysql
+```sql
 SET GLOBAL binlog-do-db=goods,auth;
 ```
 
@@ -35,7 +35,7 @@ binlog-do-db=goods,auth
 
 可以在从库执行以下命令，设定只复制 goods 数据库和 auth 数据库
 
-```mysql
+```sql
 SET GLOBAL replicate-do-db=goods,auth;
 ```
 
@@ -43,7 +43,7 @@ SET GLOBAL replicate-do-db=goods,auth;
 
 可以在从库执行以下命令，设定只复制 goods 数据库和 auth 数据库
 
-```mysql
+```sql
 CHANGE REPLICATION FILTER REPLICATE-DO-DB=(goods, order);
 ```
 
@@ -59,7 +59,7 @@ replicate-do-db=goods,order;
 
 可以在主库中执行以下命令设定忽略 goods 数据库和 auth 数据库
 
-```mysql
+```sql
 SET GLOBAL binlog-ignore-db=goods,auth;
 ```
 
@@ -75,7 +75,7 @@ binlog-ignore-db=goods,auth
 
 可以在从库执行以下命令，设定忽略 goods 数据库和 auth 数据库
 
-```mysql
+```sql
 SET GLOBAL replicate-ignore-db=goods,auth;
 ```
 
@@ -83,7 +83,7 @@ SET GLOBAL replicate-ignore-db=goods,auth;
 
 可以在从库执行以下命令，设定忽略 goods 数据库和 auth 数据库
 
-```mysql
+```sql
 CHANGE REPLICATION FILTER REPLICATE_IGNORE_DB=(goods, auth);
 ```
 
@@ -99,7 +99,7 @@ replicate-ignore-db=goods,order;
 
 可以在在从库的 MySQL 命令行设定只同步 goods 表和 orders 表
 
-```mysql
+```sql
 SET GLOBAL replicate-do-table=goods.goods,goods.orders;
 ```
 
@@ -107,7 +107,7 @@ SET GLOBAL replicate-do-table=goods.goods,goods.orders;
 
 可以在在从库的 MySQL 命令行设定只同步 goods 表和 orders 表
 
-```mysql
+```sql
 CHANGE REPLICATION FILTER REPLICATE_DO_TABLE=( goods.goods,goods.orders);
 ```
 
@@ -123,7 +123,7 @@ replicate-do-table=goods.goods,goods.orders
 
 可以在在从库的 MySQL 命令行设定只同步名称前缀为 `t_` 的表
 
-```mysql
+```sql
 CHANGE REPLICATION FILTER REPLICATE_WILD_DO_TABLE =( goods.t_%);
 ```
 
@@ -131,7 +131,7 @@ CHANGE REPLICATION FILTER REPLICATE_WILD_DO_TABLE =( goods.t_%);
 
 可以在从库的 MySQL 命令行设定忽略 orders 和 trade 表
 
-```mysql
+```sql
 SET GLOBAL replicate-ignore-table=goods.orders,goods.trade;
 ```
 
@@ -139,7 +139,7 @@ SET GLOBAL replicate-ignore-table=goods.orders,goods.trade;
 
 可以在从库的 MySQL 命令行设定忽略 orders 和 trade 表
 
-```mysql
+```sql
 CHANGE REPLICATION FILTER REPLICATE_ IGNORE_TABLE=( goods.orders,goods.trade);
 ```
 
@@ -156,7 +156,7 @@ replicate-ignore-table =goods.orders,goods.trade
 
 可以在在从库的 MySQL 命令行设定忽略名称前缀为 `o_` 的表
 
-```mysql
+```sql
 CHANGE REPLICATION FILTER REPLICATE_WILD_DO_TABLE =( goods.o_%);
 ```
 
@@ -164,6 +164,6 @@ CHANGE REPLICATION FILTER REPLICATE_WILD_DO_TABLE =( goods.o_%);
 
 设定过滤器时，可以指定通道，例如
 
-```mysql
+```sql
 CHANGE REPLICATION FILTER REPLICATE-DO-DB=(goods, auth) FOR CHANNEL ‘channel-name’;
 ```
\ No newline at end of file

data/3.MySQL高阶/6.查询优化/1. SHOW STATUS/show_status.md

@@ -11,7 +11,7 @@ Goods 数据库近期在每日高峰时段很慢，Joe 想初步的查看一下
 
 ## 答案
 
-```mysql
+```sql
 show global status; 
 ```
 
@@ -19,19 +19,19 @@ show global status;
 
 ### A
 
-```mysql
+```sql
 show status; 
 ```
 
 
 ### B
 
-```mysql
+```sql
 show session status; 
 ```
 
 ### C
 
-```mysql
+```sql
 show local status; 
 ```

data/3.MySQL高阶/6.查询优化/3. EXPLAIN/explain.md

@@ -2,7 +2,7 @@
 
 Joe 从交易服务中发现了一些高频查询和慢查询，例如
 
-```mysql
+```sql
 with recursive r(id) as (select id
                          from orders
                          where id = $1
@@ -28,7 +28,7 @@ from orders
 
 在测试库使用 
 
-```mysql
+```sql
 explain with recursive r(id) as (select id
                          from orders
                          where id = $1
@@ -43,7 +43,7 @@ from orders
 
 进行剖分，对于需要了解详细执行计划的使用
 
-```mysql
+```sql
 explain analyze with recursive r(id) as (select id
                          from orders
                          where id = 100
@@ -72,7 +72,7 @@ from orders
 
 使用
 
-```mysql
+```sql
 analyze with recursive r(id) as (select id
                          from orders
                          where id = 100