transaction

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

@@ -8,7 +8,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4)
+    price decimal(12, 4)
 );
 ```
 
@@ -22,7 +22,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     ts timestamp default now()
 );
 ```
@@ -37,7 +37,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     ts varchar(16) default now()
 );
 ```
@@ -50,7 +50,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     ts varchar(16) format 'yyyy-mm-dd'
 );
 ```
@@ -63,7 +63,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     ts date default now()
 );
 ```
@@ -76,7 +76,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     ts datetime default now()
 );
 ```

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

@@ -8,7 +8,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     ts timestamp default now()
 );
 ```
@@ -23,7 +23,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(2000),
     ts timestamp default now()
 );
@@ -39,7 +39,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description char(2000),
     ts timestamp default now()
 );
@@ -53,7 +53,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(256) default '',
     ts timestamp default now()
 );
@@ -67,7 +67,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description text(2000),
     ts timestamp default now()
 );
@@ -81,7 +81,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description tinytext(2000),
     ts timestamp default now()
 );

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

@@ -8,7 +8,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(2000),
     ts timestamp default now()
 );
@@ -24,7 +24,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(2000),
     picture blob,
     ts timestamp default now()
@@ -41,7 +41,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(2000),
     picture varchar(100000),
     ts timestamp default now()
@@ -56,7 +56,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(2000),
     picture text,
     ts timestamp default now()
@@ -71,7 +71,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(2000),
     picture binary(100000),
     ts timestamp default now()
@@ -86,7 +86,7 @@ create table orders (
     item_id int,
     amount int,
     unit_price decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(2000),
     picture varbinary(100000),
     ts timestamp default now()

data/1.MySQL初阶/5.数据修改/3.删除/delete.md

@@ -8,7 +8,7 @@ create table orders (
                         item_id int,
                         amount int,
                         unit_price decimal(12, 4),
-                        total_price decimal(12, 4),
+                        price decimal(12, 4),
                         description varchar(2000),
                         ts timestamp default now(),
                         deal bool default false
@@ -57,7 +57,7 @@ create table if not exists orders (
                         item_id int,
                         amount int,
                         unit_price decimal(12, 4),
-                        total_price decimal(12, 4),
+                        price decimal(12, 4),
                         description varchar(2000),
                         ts timestamp default now(),
                         deal bool default false

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

@@ -9,7 +9,7 @@ create table orders
     item_id     int,
     amount      int,
     unit_price  decimal(12, 4),
-    total_price decimal(12, 4),
+    price decimal(12, 4),
     description varchar(2000),
     ts          timestamp default now(),
     deal        bool      default false

data/2.MySQL中阶/1.数据库组成/7. 触发器/trigger.md

@@ -2,18 +2,17 @@
 
 SmartMarket 公司的OA数据库中包含以下结构：
 
-```postgresql
+```mysql
 create table employee(
     id serial primary key ,
-    name text,
-    dept text,
-    salary money,
-    meta jsonb default '{}'::jsonb
+    name varchar(256),
+    dept varchar(256),
+    salary decimal(12, 4)
 );
 
 create table budget(
     id serial primary key ,
-    dept text,
+    dept varchar(256),
     amount money
 )
 ```

data/2.MySQL中阶/3.聚合和分组/1. 计数/config.json

@@ -2,7 +2,9 @@
   "node_id": "mysql-ac3c072bc54749bdb82324f2b203890d",
   "keywords": [],
   "children": [],
-  "export": [],
+  "export": [
+    "count.json"
+  ],
   "keywords_must": [],
   "keywords_forbid": [],
   "group": 0

data/3.MySQL高阶/3.SQL高级技巧/6.索引和优化/daily_payment_2.json → data/2.MySQL中阶/3.聚合和分组/1. 计数/count.json

 {
   "type": "code_options",
   "author": "ccat",
-  "source": "daily_payment_2.md",
+  "source": "count.md",
   "notebook_enable": false,
-  "exercise_id": "ffde3c073ee848a093c5edc733c7a61c"
+  "exercise_id": "550bc91b4d7849ef8463a807871d145c"
 }
\ No newline at end of file

data/2.MySQL中阶/3.聚合和分组/1. 计数/count.md

+# count 练习
+
+Joe 建立了一个名为items的表
+
+```
+mysql> select * from items;
++----+-----------+
+| id | item      |
++----+-----------+
+|  1 |         2 |
+|  2 |      NULL |
+|  3 |         9 |
+|  4 | 534214123 |
++----+-----------+
+```
+
+当他执行
+
+```mysql
+select count(*), count(item) from items;
+```
+
+会得到什么结果？
+
+## 答案
+
+```
+3, 4
+```
+
+## 选项
+
+### A
+
+```
+4, NULL
+```
+
+### B
+
+```
+3, 3
+```
+
+### C
+
+```
+1, 0
+```
+
+### D
+
+```
+NULL,  NULL
+```
+
+### E
+
+```
+4, 4
+```
\ No newline at end of file

data/2.MySQL中阶/3.聚合和分组/2. 求和/config.json

@@ -2,7 +2,9 @@
   "node_id": "mysql-c5654c150993418a96f692496837fbb7",
   "keywords": [],
   "children": [],
-  "export": [],
+  "export": [
+    "sum.json"
+  ],
   "keywords_must": [],
   "keywords_forbid": [],
   "group": 0

data/2.MySQL中阶/3.聚合和分组/2. 求和/sum.json

+{
+  "type": "code_options",
+  "author": "ccat",
+  "source": "sum.md",
+  "notebook_enable": false,
+  "exercise_id": "6ac9bb99a6684023ad80fde36ea32f6a"
+}
\ No newline at end of file

data/2.MySQL中阶/3.聚合和分组/2. 求和/sum.md

+# 求和练习
+
+Joe 想要得到 orders 表
+
+```mysql
+create table orders (
+                        id int primary key auto_increment,
+                        item_id int,
+                        amount int,
+                        unit_price decimal(12, 4),
+                        total decimal(12, 4),
+                        description varchar(2000),
+                        ts timestamp default now(),
+                        deal bool default false
+);
+```
+
+中所有单价(unit_price)超过 1000 的订单中，已成交（deal 为 true）的总值（total），这个查询应该是：
+
+## 答案
+
+```mysql
+select sum(total) from orders where deal and unit_price > 1000;
+```
+
+## 选项
+
+### A
+
+```mysql
+select sum(total) from orders where deal and unit_price > 1000;
+```
+
+### B
+
+```mysql
+select sum(total) from orders having deal and unit_price > 1000;
+```
+
+### C
+
+```mysql
+select sum(total) from orders group by deal having unit_price > 1000;
+```
+
+### D
+
+```mysql
+select sum(total) from orders having deal and unit_price > 1000;
+```
\ No newline at end of file

data/2.MySQL中阶/3.聚合和分组/3.最小值/config.json

@@ -2,7 +2,9 @@
   "node_id": "mysql-c1652108441c424197c0c3c526e4831c",
   "keywords": [],
   "children": [],
-  "export": [],
+  "export": [
+    "min.json"
+  ],
   "keywords_must": [],
   "keywords_forbid": [],
   "group": 0

data/2.MySQL中阶/3.聚合和分组/3.最小值/min.json

+{
+  "type": "code_options",
+  "author": "ccat",
+  "source": "min.md",
+  "notebook_enable": false,
+  "exercise_id": "c25658691a9043eab38b61aec9ad827c"
+}
\ No newline at end of file

data/2.MySQL中阶/3.聚合和分组/3.最小值/min.md

+# 最小值练习
+
+Joe 想要得到 employee 表
+
+```mysql
+create table employee
+(
+    id     serial primary key,
+    name   varchar(256),
+    dept   varchar(256),
+    salary decimal(12, 4)
+);
+```
+
+中每个部门工资最低的员工的工资信息，这条查询应该怎么写？
+
+## 答案
+
+```mysql
+select dept, min(salary) from employee group by dept;
+```
+
+## 选项
+
+### A
+
+```mysql
+select dept, min(salary) from employee;
+```
+
+### B
+
+```mysql
+select dept, min(salary) from employee;
+```
+
+### C
+
+```mysql
+select dept, min(salary) from employee;
+```
+
+### D
+
+```mysql
+select sum(total) from orders having deal and unit_price > 1000;
+```
\ No newline at end of file

data/2.MySQL中阶/3.聚合和分组/4. 最大值/config.json

@@ -2,7 +2,9 @@
   "node_id": "mysql-77042376726743bea5c97e82a67a2016",
   "keywords": [],
   "children": [],
-  "export": [],
+  "export": [
+    "max.json"
+  ],
   "keywords_must": [],
   "keywords_forbid": [],
   "group": 0

data/2.MySQL中阶/3.聚合和分组/4. 最大值/max.json

+{
+  "type": "code_options",
+  "author": "ccat",
+  "source": "max.md",
+  "notebook_enable": false,
+  "exercise_id": "7e56c3165ccc46f5b2ffb3d0eba53eff"
+}
\ No newline at end of file

data/2.MySQL中阶/3.聚合和分组/4. 最大值/max.md

+# 最大值练习
+
+利用员工信息表：
+
+```mysql
+create table employee
+(
+    id     serial primary key,
+    name   varchar(256),
+    dept   varchar(256),
+    salary decimal(12, 4)
+);
+```
+
+Joe 做了一些关于 max 函数的练习，其中不正确的是：
+
+## 答案
+
+```mysql
+select id, dept, max(salary) as salary, name 
+from employee
+group by dept
+```
+
+可以得到每个部门工资最高的员工的全部信息。
+
+## 选项
+
+### A
+
+```mysql
+select dept, max(salary) as salary
+from employee
+group by dept
+```
+
+可以得到每个部门的最高工资。
+
+### B
+
+```mysql
+select max(salary) as salary
+from employee
+```
+
+可以得到全部员工中最高的工资。
+
+### C
+
+```mysql
+select dept, sum(salary)
+from employee
+group by dept
+having max(salary) < 20000
+```
+
+可以得到员工最高工资不超过两万的部门及其总的工资开支
+
+### D
+
+```mysql
+select dept, min(salary)
+from employee
+group by dept
+having max(salary) > 50000
+```
+
+可以得到员工最高工资超过五万的部门，及其最低工资的清单

data/2.MySQL中阶/4.连接查询/5. 复杂连接/salary.md

@@ -2,12 +2,12 @@
 
 现有员工信息表如下：
 
-```postgresql
+```mysql
 create table employee
 (
     id     serial primary key,
-    name   text,
-    dept   text,
+    name   varchar(256),
+    dept   varchar(256),
     salary money
 );
 ```
@@ -16,7 +16,7 @@ create table employee
 
 ## 答案
 
-```postgresql
+```mysql
 select l.id, l.name, l.dept, l.salary
 from employee as l
          join (select max(salary) as salary, dept
@@ -29,7 +29,7 @@ from employee as l
 
 ### select 与 group by 不匹配
 
-```postgresql
+```mysql
 select id, name, dept, max(salary)
 from employee
 group by dept;
@@ -37,7 +37,7 @@ group by dept;
 
 ### group by 不对
 
-```postgresql
+```mysql
 select id, name, dept, max(salary)
 from employee
 group by dept, id, name;
@@ -45,7 +45,7 @@ group by dept, id, name;
 
 ### group by 不对
 
-```postgresql
+```mysql
 select id, name, dept, max(salary)
 from employee
 group by dept, id, name
@@ -54,7 +54,7 @@ having salary = max(salary);
 
 ### 结构错误
 
-```postgresql
+```mysql
 select id, name, dept, max(salary)
 from employee
 where salary = max(salary)

data/2.MySQL中阶/4.连接查询/customer_order.md

 # 客户和订单
 
-我们现在看下面这个客户/订单系统
+Goods 中有客户/订单系统如下：
 
-```postgresql
+```mysql
 create table customers
 (
     id           serial primary key,
-    company_name text,
-    address      text,
-    city         text,
-    state        text
+    company_name varchar(256),
+    address      varchar(1024),
+    city         varchar(256),
+    state        varchar(256)
 );
 
 create table products
 (
     id          serial primary key,
-    description text,
-    unit_price  money
+    description varchar(1024),
+    unit_price  decimal(12, 4)
 );
 
 create table orders

data/2.MySQL中阶/6.子查询/1.相关子查询/config.json

+{
+  "node_id": "mysql-f045eeff32bd449c83afc76abdd65344",
+  "keywords": [],
+  "children": [],
+  "export": [
+    "subquery.json"
+  ],
+  "keywords_must": [],
+  "keywords_forbid": []
+}
\ No newline at end of file

data/2.MySQL中阶/6.子查询/1.相关子查询/subquery.md

+# 子查询
+
+现有员工表
+
+```mysql
+create table employee
+(
+    id     serial primary key,
+    name   varchar(256),
+    dept   varchar(256),
+    salary decimal(12, 4)
+);
+```
+
+Joe 希望找出比销售部（dept 为 sale）工资最高的员工工资更高的那部分人，查询出他们的完整信息，下面哪一项可以满足要求？
+
+## 答案
+
+```mysql
+select id, name, dept, salary
+from employee
+where salary > (select max(salary)
+                from employee
+                where dept = 'sale')
+```
+
+## 选项
+
+### A
+
+```mysql
+select id, name, dept, salary
+from employee
+where dept = 'sale'
+group by dept
+having salary > max(salary)
+```
+
+### B
+
+```mysql
+select l.id, l.name, l.dept, l.salary
+from employee as l
+         join employee as r on l.salary > max(r.salary)
+where r.dept = 'sale'
+group by r.dept 
+```
+
+### C
+
+```mysql
+select id, name, dept, salary
+from employee
+having salary > (select max(salary) from employee where dept = 'sale')
+```
+
+
+

data/2.MySQL中阶/6.子查询/1.ANY/config.json → data/2.MySQL中阶/6.子查询/2. ANY/config.json

 {
   "node_id": "mysql-6bb279fa10fa4633a3af51ff7001f5ce",
-  "keywords": [],
+  "keywords": ["subquery", "子查询", "any"],
   "children": [],
   "export": [],
   "keywords_must": [],

data/2.MySQL中阶/6.子查询/subquery.md

@@ -2,13 +2,13 @@
 
 现有员工表
 
-```postgresql
+```mysql
 create table employee
 (
-    id     serial primary key,
-    name   text,
-    dept   text,
-    salary money
+    id     int primary key auto_increment,
+    name   varchar(256),
+    dept   varchar(256),
+    salary decimal(12, 4)
 )
 ```
 
@@ -16,7 +16,7 @@ create table employee
 
 ## 答案
 
-```postgresql
+```mysql
 select id, name, dept, salary
 from employee
 where salary > (select max(salary)
@@ -28,7 +28,7 @@ where salary > (select max(salary)
 
 ### A
 
-```postgresql
+```mysql
 select id, name, dept, salary
 from employee
 where dept = 'sale'
@@ -38,7 +38,7 @@ having salary > max(salary)
 
 ### B
 
-```postgresql
+```mysql
 select l.id, l.name, l.dept, l.salary
 from employee as l
          join employee as r on l.salary > max(r.salary)
@@ -48,7 +48,7 @@ group by r.dept
 
 ### C
 
-```postgresql
+```mysql
 select id, name, dept, salary
 from employee
 having salary > (select max(salary) from employee where dept = 'sale')

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

 # 获取连续区间
 
-SmartMarket 交易所的系统中，所有订单在生成时，都从一个 PostgreSQL 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：
+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：
 
-```postgresql
+```mysql
 create table orders
 (
     id      integer primary key,
-    meta    jsonb default '{}'::jsonb,
-    content jsonb default '{}'::jsonb
+    content json
     -- ignore other definitions...
 );
 ```
 
-后续的结算系统需要连续的获取订单，以便处理一些顺序敏感的业务。但是撮合发生在很多个异步节点上，它们只能保证最终会将所有订单都保存到 orders 表，确保 id 列最终是连续的，但是最新插入的一段记录集有可能不连续。而我们希望结算系统成批
-的读取数据，以优化性能，那么在结算系统有它最后处理的订单id的前提下，下面哪一个查询可以确保从这个id向前读取 id 连续 的一批订单？
+后续的结算系统需要连续的获取订单，以便处理一些顺序敏感的业务。但是撮合发生在很多个异步节
+点上，它们只能保证最终会将所有订单都保存到 orders 表，确保 id 列最终是连续的，但是最新
+插入的一段记录集有可能不连续。而我们希望结算系统成批的读取数据，以优化性能，那么在结算系
+统有它最后处理的订单id的前提下，下面哪一个查询可以确保从这个id向前读取 id 连续 的一批
+订单？
 
 ## 答案
 
-```postgresql
+```mysql
 with recursive r(id) as (select id
                          from orders
                          where id = $1
@@ -25,7 +28,7 @@ with recursive r(id) as (select id
                          select d.id
                          from orders as d
                                   join r on d.id = r.id + 1)
-select orders.id, meta, content
+select orders.id, content
 from orders
          join r on orders.id = r.id;
 ```
@@ -38,8 +41,8 @@ from orders
 
 ### B
 
-```postgresql
-select data.id, meta, content
+```mysql
+select data.id, content
 from orders
          join orders as r on orders.id = r.id - 1
 where id = $1;
@@ -47,15 +50,15 @@ where id = $1;
 
 ### C
 
-```postgresql
-select id, meta, content
+```mysql
+select id, content
 from orders
 where id in (select id from orders where id = id + 1);
 ```
 
 ### D
 
-```postgresql
+```mysql
 with r as (select id
            from orders
            where id = $1
@@ -63,7 +66,7 @@ with r as (select id
            select d.id
            from orders as d
                     join r on d.id = r.id + 1)
-select orders.id, meta, content
+select orders.id, content
 from orders
          join r on orders.id = r.id;
 ```
\ No newline at end of file

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

@@ -2,7 +2,7 @@
 
 现有员工信息表如下：
 
-```postgresql
+```mysql
 create table employee
 (
     id     serial primary key,
@@ -16,7 +16,7 @@ create table employee
 
 ## 答案
 
-```postgresql
+```mysql
 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
@@ -27,7 +27,7 @@ where r <= 5;
 
 ### 结构错误
 
-```postgresql
+```mysql
 select id, name, dept, max(salary) as salary
 from employee
 group by dept
@@ -36,7 +36,7 @@ having id < 6;
 
 ### 结构错误
 
-```postgresql
+```mysql
 select l.id, l.name, l.dept, l.salary
 from employee as l
          join (select max(salary) as salary, dept
@@ -48,7 +48,7 @@ where count(r.id) <= 5;
 
 ### 结构错误
 
-```postgresql
+```mysql
 select l.id, l.name, l.dept, l.salary
 from employee as l
          join (select max(salary, 5) as salary, dept
@@ -59,7 +59,7 @@ from employee as l
 
 ### 结构错误
 
-```postgresql
+```mysql
 select id, name, dept, salary, rank() over (partition by dept order by salary desc) as r
 from employee
 where r <= 5;
@@ -67,7 +67,7 @@ where r <= 5;
 
 ### 结构错误
 
-```postgresql
+```mysql
 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/3.SQL高级技巧/3.透视表 /pivot.md

@@ -2,12 +2,11 @@
 
 现有销售记录表
 
-```postgresql
+```mysql
 create table sales(
     id serial primary key ,
     sku_id integer not null ,
-    amount money,
-    meta jsonb default '{}'::jsonb,
+    amount decimal(12, 4),
     created_at timestamp default now()
 );
 create index on sales(created_at);
@@ -17,20 +16,20 @@ create index on sales(created_at);
 
 ## 答案
 
-```postgresql
+```mysql
 select sku_id, 
-       sum(case extract(month from created_at) when 1 then amount else 0::money end) as Jan,
-       sum(case extract(month from created_at) when 2 then amount else 0::money end) as Feb,
-       sum(case extract(month from created_at) when 3 then amount else 0::money end) as Mar,
-       sum(case extract(month from created_at) when 4 then amount else 0::money end) as Apr,
-       sum(case extract(month from created_at) when 5 then amount else 0::money end) as May,
-       sum(case extract(month from created_at) when 6 then amount else 0::money end) as June,
-       sum(case extract(month from created_at) when 7 then amount else 0::money end) as July,
-       sum(case extract(month from created_at) when 8 then amount else 0::money end) as Aug,
-       sum(case extract(month from created_at) when 9 then amount else 0::money end) as Sept,
-       sum(case extract(month from created_at) when 10 then amount else 0::money end) as Oct,
-       sum(case extract(month from created_at) when 11 then amount else 0::money end) as Nov,
-       sum(case extract(month from created_at) when 12 then amount else 0::money end) as Dec
+       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,
+       sum(case extract(month from created_at) when 3 then amount else 0 end) as Mar,
+       sum(case extract(month from created_at) when 4 then amount else 0 end) as Apr,
+       sum(case extract(month from created_at) when 5 then amount else 0 end) as May,
+       sum(case extract(month from created_at) when 6 then amount else 0 end) as June,
+       sum(case extract(month from created_at) when 7 then amount else 0 end) as July,
+       sum(case extract(month from created_at) when 8 then amount else 0 end) as Aug,
+       sum(case extract(month from created_at) when 9 then amount else 0 end) as Sept,
+       sum(case extract(month from created_at) when 10 then amount else 0 end) as Oct,
+       sum(case extract(month from created_at) when 11 then amount else 0 end) as Nov,
+       sum(case extract(month from created_at) when 12 then amount else 0 end) as Dec
 from sales
 where created_at between '2020-01-01'::timestamp and '2021-01-01'::timestamp
 group by sku_id; 
@@ -40,7 +39,7 @@ group by sku_id;
 
 ### 格式不相符
 
-```postgresql
+```mysql
 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
@@ -49,7 +48,7 @@ group by 1, 2;
 
 ### 计算逻辑错误
 
-```postgresql
+```mysql
 select sku_id, 
        sum(amount) as Jan,
        sum(amount) as Feb,
@@ -70,7 +69,7 @@ group by sku_id, extract(month from created_at);
 
 ### 计算格式错误
 
-```postgresql
+```mysql
 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/3.SQL高级技巧/4.写入和冲突/score.md

@@ -2,7 +2,7 @@
 
 现有一个表
 
-```postgresql
+```mysql
 create table book_in(
     login integer primary key ,
     score integer default 0
@@ -14,15 +14,15 @@ create table book_in(
 
 ## 答案
 
-```postgresql
-insert into book_in(login, score) values ($1, $2) on conflict do update set score=$2;
+```mysql
+insert into book_in(login, score) values ($1, $2) on DUPLICATE KEY update score=$2;
 ```
 
 ## 选项
 
 ### A
 
-```postgresql
+```mysql
 try
     insert into book_in(login, score) values ($1, $2);
 catch
@@ -33,18 +33,18 @@ finally
 
 ### B
 
-```postgresql
+```mysql
 insert into book_in(login, score) select $1, $2;
 ```
 
 ### C
 
-```postgresql
+```mysql
 replace book_in(login, score) select $1, $2;
 ```
 
 ### D
 
-```postgresql
+```mysql
 upsert into book_in(login, score) select $1, $2;
 ```

data/3.MySQL高阶/3.SQL高级技巧/5.事务/transaction.md

@@ -2,27 +2,32 @@
 
 现有 test1 表如下
 
-```postgresql
+```mysql
 create table test1(a integer primary key );
 ```
 
 我们执行下面的语句
 
-```postgresql
+```mysql
 CREATE PROCEDURE transaction_test1()
-LANGUAGE plpgsql
-AS $$
 BEGIN
-    FOR i IN 0..9 LOOP
-        INSERT INTO test1 (a) VALUES (i);
-        IF i % 2 = 0 THEN
+    declare idx int;
+    set idx = 0;
+    iter: LOOP
+        start transaction ;
+        INSERT INTO test1 (a) VALUES (idx);
+        IF (idx % 2) = 0 THEN
             COMMIT;
         ELSE
             ROLLBACK;
         END IF;
-    END LOOP;
+        IF idx < 10 THEN
+            set idx = idx + 1;
+            ITERATE iter;
+        END IF;
+        LEAVE iter;
+    END LOOP iter;
 END;
-$$;
 
 CALL transaction_test1();
 ```
@@ -31,13 +36,13 @@ CALL transaction_test1();
 
 ## 答案
 
-每当循环迭代到偶数的时候提交插入，最终 test1 表中是`0,2,4,6,8`。
+每当循环迭代到偶数的时候提交插入，最终 test1 表中是`0,2,4,6,8,10`。
 
 ## 选项
 
 ### A
 
-以最后一次提交为准，最终 test1 表中是 0 到 9 共九个数字。
+以最后一次提交为准，最终 test1 表中是 0 到 10 共11个数字。
 
 ### B
 

data/3.MySQL高阶/3.SQL高级技巧/6.索引和优化/config.json

@@ -8,8 +8,7 @@
   ],
   "children": [],
   "export": [
-    "daily_payment.json",
-    "daily_payment_2.json"
+    "daily_payment.json"
   ],
   "keywords_must": [
     "索引",

data/3.MySQL高阶/3.SQL高级技巧/6.索引和优化/daily_payment.md

@@ -2,27 +2,28 @@
 
 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
 
-```postgresql
-select payment_date::date as day, sum(amount)
+```mysql
+select date(payment_date) as day, sum(amount)
 from payment
-where (payment_date::date) between $1 and 'yesterday'::date
-group by payment_date::date;
+where date(payment_date) between $1 and DATE_SUB(CURDATE(), INTERVAL 1 DAY)
+group by date(payment_date);
 ```
 
 现在这个查询很慢，payment 表的信息如下：
 
 ```text
-                                             Table "public.payment"
-    Column    |            Type             | Collation | Nullable |                   Default
---------------+-----------------------------+-----------+----------+---------------------------------------------
- payment_id   | integer                     |           | not null | nextval('payment_payment_id_seq'::regclass)
- customer_id  | smallint                    |           | not null |
- staff_id     | smallint                    |           | not null |
- rental_id    | integer                     |           | not null |
- amount       | numeric(5,2)                |           | not null |
- payment_date | timestamp without time zone |           | not null |
-Indexes:
-    "payment_pkey" PRIMARY KEY, btree (payment_id)
+mysql> desc payment;
++---------------+---------------+------+-----+---------+----------------+
+| Field         | Type          | Null | Key | Default | Extra          |
++---------------+---------------+------+-----+---------+----------------+
+| payment_id    | int           | NO   | PRI | NULL    | auto_increment |
+| customer_id   | int           | YES  |     | NULL    |                |
+| staff_id      | int           | YES  |     | NULL    |                |
+| rental_id     | int           | YES  |     | NULL    |                |
+| amount        | decimal(12,8) | YES  |     | NULL    |                |
+| pathment_date | timestamp     | YES  |     | NULL    |                |
++---------------+---------------+------+-----+---------+----------------+
+6 rows in set (0.12 sec)
 ```
 
 应该如何优化这个查询？
@@ -31,8 +32,8 @@ Indexes:
 
 建立表达式索引
 
-```postgresql
-create index on payment((payment_date::date));
+```mysql
+alter table payment add index idx_payment_date((date(payment_date)));
 ```
 
 ## 选项
@@ -41,16 +42,16 @@ create index on payment((payment_date::date));
 
 建立视图
 
-```postgresql
-create view view_daily_payment as select payment_date::date as day, amount from payment;
+```mysql
+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
 
-```postgresql
+```mysql
 select day, sum(amount) 
 from view_daily_payment
-where day between $1 and 'yesterday'::date
+where day between $1 and DATE_SUB(CURDATE(), INTERVAL 1 DAY)
 group by day 
 ```
 
@@ -58,23 +59,23 @@ group by day
 
 在 payment_date 列上建立索引
 
-```postgresql
-create index on payment(payment_date);
+```mysql
+create index idx_payment_date on payment(payment_date);
 ```
 
 ### 可以简化语句，但对优化没有帮助
 
 建立计算列
 
-```postgresql
-alter table payment add day date generated always as ( payment_date::date ) stored 
+```mysql
+alter table payment add day date generated always as (date(payment_date)) stored; 
 ```
 
 然后使用它改写查询
 
-```postgresql
+```mysql
 select day as day, sum(amount)
 from payment
-where day between $1 and 'yesterday'::date
+where day between $1 and date('yesterday')
 group by day;
 ```
\ No newline at end of file

data/3.MySQL高阶/3.SQL高级技巧/6.索引和优化/daily_payment_2.md

-# 每日报表优化
-
-# 每日报表
-
-统计过去一段时间的数据，你发现 payment 表上每天的订单量很大，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
-早止当天，总是在历史上某一个日期段内查询
-
-```postgresql
-select payment_date::date as day, sum(amount)
-from payment
-where (payment_date::date) between $1 and $2
-group by payment_date::date;
-```
-
-payment 表的信息如下：
-
-```text
-                                             Table "public.payment"
-    Column    |            Type             | Collation | Nullable |                   Default
---------------+-----------------------------+-----------+----------+---------------------------------------------
- payment_id   | integer                     |           | not null | nextval('payment_payment_id_seq'::regclass)
- customer_id  | smallint                    |           | not null |
- staff_id     | smallint                    |           | not null |
- rental_id    | integer                     |           | not null |
- amount       | numeric(5,2)                |           | not null |
- payment_date | timestamp without time zone |           | not null |
-Indexes:
-    "payment_pkey" PRIMARY KEY, btree (payment_id)
-```
-
-怎样做是最有效的？
-
-##  答案
-
-建立物化视图并建立索引。
-
-```postgresql
-create materialized view view_daily_payment as 
-    select payment_date::date as day, sum(amount) as amount from payment group by day;
-    
-create index on view_daily_payment(day);
-
-```
-
-使用
-
-```postgresql
-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
-
-```postgresql
-REFRESH MATERIALIZED VIEW view_daily_payment;
-```
-
-## 选项
-
-### 不会优化 sum 和 group by
-
-在 payment_date 列上建立索引
-
-```postgresql
-create index on payment(payment_date);
-```
-
-### 不会优化 sum 
-
-建立计算列
-
-```postgresql
-alter table payment add day date generated always as ( payment_date::date ) stored 
-```
-
-然后使用它改写查询
-
-```postgresql
-select day as day, sum(amount)
-from payment
-where day between $1 and 'yesterday'::date
-group by day;
-```
-
-### 优化了日期查询，但是不会优化统计过程
-
-建立表达式索引
-
-```postgresql
-create index on payment((payment_date::date));
-```
-
-### 不做物化，对查询速度不会有显著改善
-
-建立视图
-
-```postgresql
-create view view_daily_payment as select payment_date::date as day, amount from payment;
-```
-
-然后在视图 view_daily_payment 上执行
-
-```postgresql
-select day, sum(amount) 
-from view_daily_payment
-where day between $1 and 'yesterday'::date
-group by day 
-```
\ No newline at end of file

data/tree.json

@@ -547,7 +547,11 @@
                   {
                     "CASE": {
                       "node_id": "mysql-8e6cd4d5f4b446a2bc3f5402de9bd49c",
-                      "keywords": [],
+                      "keywords": [
+                        "case",
+                        "pivot",
+                        "透视表"
+                      ],
                       "children": [],
                       "keywords_must": [],
                       "keywords_forbid": []
@@ -803,7 +807,16 @@
                 ],
                 "children": [
                   {
-                    "ANY": {
+                    "相关子查询": {
+                      "node_id": "mysql-f045eeff32bd449c83afc76abdd65344",
+                      "keywords": [],
+                      "children": [],
+                      "keywords_must": [],
+                      "keywords_forbid": []
+                    }
+                  },
+                  {
+                    " ANY": {
                       "node_id": "mysql-6bb279fa10fa4633a3af51ff7001f5ce",
                       "keywords": [],
                       "children": [],

gears/sql/orders.sql

@@ -3,7 +3,7 @@ create table orders (
                         item_id int,
                         amount int,
                         unit_price decimal(12, 4),
-                        total_price decimal(12, 4),
+                        total decimal(12, 4),
                         description varchar(2000),
                         ts timestamp default now(),
                         deal bool default false

gears/sql/payment.sql

+create table payment(
+    payment_id int primary key auto_increment,
+    customer_id int,
+    staff_id int,
+    rental_id int,
+    amount decimal(12, 8),
+    payment_date timestamp
+)
\ No newline at end of file