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skill_tree_mysql
提交 ba97f6ea 编写于 作者: M Mars Liu
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修正左连接题目错误；代码排版

上级 2778a741
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Showing with 1071 addition and 645 deletion
data/1.MySQL初阶/2.安装和登录/2.登录/prepare.md
浏览文件 @ ba97f6ea
......@@ -25,8 +25,13 @@ mysql mysql
```
创建数据库用户 joe 并授权：
```sql
create user 'joe'@'localhost' identified by 'joe';
grant all privileges on *.* to `joe`@`localhost`;
create user
'joe'@'localhost'
identified by 'joe';
grant all privileges
on *.* to `joe`@`localhost`;
flush privileges ;
```
......@@ -41,7 +46,9 @@ mysql mysql
```
为 joe 授权
```sql
grant all privileges on *.* to joe;
grant all
privileges on *.* to joe;
flush privileges ;
```
......@@ -55,7 +62,9 @@ mysql mysql
为 joe 授权
```sql
grant all privileges on *.* to joe;
grant all
privileges on *.* to joe;
flush privileges ;
```
......@@ -68,7 +77,10 @@ mysql mysql
创建数据库用户 joe
```sql
create user 'joe'@'localhost' identified by 'joe';
create user
'joe'@'localhost'
identified by 'joe';
flush privileges ;
```
......@@ -81,7 +93,12 @@ mysql mysql
```
创建数据库用户 joe 并授权：
```sql
create user 'joe'@'%' identified by 'joe';
grant all privileges on *.* to joe;
create user
'joe'@'%'
identified by 'joe';
grant all
privileges on *.* to joe;
flush privileges ;
```
data/1.MySQL初阶/5.数据修改/1.插入/config.json
浏览文件 @ ba97f6ea
{
"node_id": "mysql-fcca525ab0f04f16834ded9b2b3f38a4",
"keywords": ["insert", "插入"],
"keywords": [
"insert",
"插入"
],
"children": [],
"export": [
"insert.json"
],
"keywords_must": [
["mysql", "插入"]
[
"mysql",
"插入"
]
],
"keywords_forbid": [],
"group": 1
......
data/1.MySQL初阶/5.数据修改/1.插入/insert.md
浏览文件 @ ba97f6ea
......@@ -26,8 +26,24 @@ create unique index idx_book_isbn on book(isbn);
## 答案
```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';
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';
```
## 选项
......@@ -35,27 +51,83 @@ insert into book(title, price, isbn, publish_at) select 'a other book title', 25
### 唯一键冲突
```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';
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
```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';
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
```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';
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
```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';
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
浏览文件 @ ba97f6ea
......@@ -24,7 +24,9 @@ Joe 希望修改销售部(dept 字段为 sale)员工 Dora Muk 的工资，将其
## 答案
```sql
update employee set salary = salary + 1000 where dept = 'sale' and name = 'Dora Muk';
update employee set
salary = salary + 1000
where dept = 'sale' and name = 'Dora Muk';
```
## 选项
......@@ -32,19 +34,23 @@ update employee set salary = salary + 1000 where dept = 'sale' and name = 'Dora
### 过滤条件不严谨
```sql
update employee set salary = salary + 1000 where name = 'Dora Muk';
update employee set
salary = salary + 1000
where name = 'Dora Muk';
```
### 缺少过滤条件
```sql
update employee set salary = salary + 1000;
update employee set
salary = salary + 1000;
```
### 错误的赋值语句
```sql
update employee set salary += 1000;
update employee set
salary += 1000;
```
data/1.MySQL初阶/5.数据修改/3.删除/delete.md
浏览文件 @ ba97f6ea
......@@ -4,14 +4,14 @@
```sql
create table orders (
id int primary key auto_increment,
item_id int,
amount int,
unit_price decimal(12, 4),
price decimal(12, 4),
description varchar(2000),
ts timestamp default now(),
deal bool default false
id int primary key auto_increment,
item_id int,
amount int,
unit_price decimal(12, 4),
price decimal(12, 4),
description varchar(2000),
ts timestamp default now(),
deal bool default false
);
```
......@@ -60,14 +60,14 @@ from orders;
```sql
drop table orders;
create table if not exists orders (
id int primary key auto_increment,
item_id int,
amount int,
unit_price decimal(12, 4),
price decimal(12, 4),
description varchar(2000),
ts timestamp default now(),
deal bool default false
id int primary key auto_increment,
item_id int,
amount int,
unit_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/1.SELECT/config.json
浏览文件 @ ba97f6ea
{
"node_id": "mysql-f5527eae7f3148108c92ff99a6d4ed4a",
"keywords": ["查询", "select"],
"keywords": [
"查询",
"select"
],
"children": [],
"export": [
"select.json"
],
"keywords_must": [
["mysql", "select"]
[
"mysql",
"select"
]
],
"keywords_forbid": [],
"group": 1
......
data/1.MySQL初阶/6.数据查询/1.SELECT/select.md
浏览文件 @ ba97f6ea
......@@ -39,7 +39,9 @@ select * from employee where dept = 'hr';
### D
```sql
select id, name, dept, salary from employee where salary > 10000;
select id, name, dept, salary
from employee
where salary > 10000;
```
### E
......
data/1.MySQL初阶/6.数据查询/2.WHERE/config.json
浏览文件 @ ba97f6ea
{
"node_id": "mysql-91cc9c73e58945d3ba654370a057a1c7",
"keywords": ["查询", "select", "where"],
"keywords": [
"查询",
"select",
"where"
],
"children": [],
"export": [
"where.json"
],
"keywords_must": [
["mysql", "where"]
[
"mysql",
"where"
]
],
"keywords_forbid": [],
"group": 1
......
data/1.MySQL初阶/6.数据查询/2.WHERE/where.md
浏览文件 @ ba97f6ea
......@@ -40,7 +40,9 @@ where date(ts) = '2022-05-25'
```sql
select id
from (select * from orders where date(ts) = '2022-05-25') as o
from (select *
from orders
where date(ts) = '2022-05-25') as o
where unit_prise < 20;
```
......@@ -58,7 +60,8 @@ where date(ts) = '2022-05-25'
```sql
select id
from orders
if date(ts) = '2022-05-25' or unit_prise < 20;
if date(ts) = '2022-05-25'
or unit_prise < 20;
```
### D
......
data/1.MySQL初阶/6.数据查询/3.运算符/config.json
浏览文件 @ ba97f6ea
......@@ -9,7 +9,10 @@
"geo.json"
],
"keywords_must": [
["mysql", "运算符"]
[
"mysql",
"运算符"
]
],
"keywords_forbid": [],
"group": 1
......
data/1.MySQL初阶/6.数据查询/3.运算符/geo.md
浏览文件 @ ba97f6ea
......@@ -22,7 +22,8 @@ create table points(
## 答案
```sql
select id, sqrt(x^2 + y^2) from points;
select id, sqrt(x^2 + y^2)
from points;
```
## 选项
......@@ -30,23 +31,30 @@ select id, sqrt(x^2 + y^2) from points;
### A
```sql
select sqrt(vx+vy) from (select x^2 as vx, y^2 as vy from points) as t;
select sqrt(vx+vy)
from (
select x^2 as vx, y^2 as vy
from points) as t;
```
### B
```sql
select sqrt(vx + vy) from points where x^2 as vx, y^2 as vy ;
select sqrt(vx + vy)
from points
where x^2 as vx, y^2 as vy ;
```
### C
```sql
select id + sqrt(x^2 + y^2) from points;
select id + sqrt(x^2 + y^2)
from points;
```
### D
```sql
select id || sqrt(x^2 + y^2) from points;
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/3.存储过程和函数/create_procedure.md
浏览文件 @ ba97f6ea
......@@ -14,7 +14,10 @@ Joe 希望这个计算更紧凑一些，在已经有 individual_income_tax 的
## 答案
```sql
create procedure sp_idt(in salary decimal(12, 4), out tax decimal(12, 4), out take_home decimal(12, 4))
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);
set take_home = salary - tax;
......@@ -26,7 +29,9 @@ end;
### A
```sql
create procedure sp_idt(salary decimal(12, 4)) returns (tax decimal(12, 4), take_home decimal(12, 4))
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);
set take_home = salary - tax;
......@@ -37,7 +42,8 @@ end;
```sql
create procedure sp_idt(salary decimal(12, 4)) returns (decimal(12, 4), decimal(12, 4))
create procedure sp_idt(salary decimal(12, 4))
returns (decimal(12, 4), decimal(12, 4))
begin
declare tax, take_home decimal(12, 4);
set tax = individual_income_tax(salary);
......
data/2.MySQL中阶/1.数据库组成/5. 触发器/audit.md
浏览文件 @ ba97f6ea
......@@ -45,13 +45,44 @@ create table orders_log
## 答案
```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');
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)
values(OLD.id, OLD.item_id, OLD.amount, OLD.unit_price, OLD.total, OLD.description, OLD.ts, 'out');
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');
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)
values(OLD.id,
OLD.item_id,
OLD.amount,
OLD.unit_price,
OLD.total,
OLD.description,
OLD.ts,
'out');
```
## 选项
......@@ -60,8 +91,23 @@ create trigger out_orders after delete on orders
```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');
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');
```
......@@ -70,8 +116,23 @@ create trigger in_orders after insert on orders
```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)
values(OLD.id, OLD.item_id, OLD.amount, OLD.unit_price, OLD.total, OLD.description, OLD.ts, 'out');
for each row insert into orders_log(
id,
item_id,
amount,
unit_price,
total,
description,
ts,
direction)
values(OLD.id,
OLD.item_id,
OLD.amount,
OLD.unit_price,
OLD.total,
OLD.description,
OLD.ts,
'out');
```
......@@ -79,17 +140,63 @@ create trigger out_orders after delete on orders
```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');
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');
after delete on orders
for each row insert into orders_log(id, item_id, amount, unit_price, total, description, ts, direction)
values(OLD.id, OLD.item_id, OLD.amount, OLD.unit_price, OLD.total, OLD.description, OLD.ts, 'out');
for each row insert into orders_log(
id,
item_id,
amount,
unit_price,
total,
description,
ts,
direction)
values(OLD.id,
OLD.item_id,
OLD.amount,
OLD.unit_price,
OLD.total,
OLD.description,
OLD.ts,
'out');
```
### D
```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');
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');
```
\ No newline at end of file
data/2.MySQL中阶/11.用户和权限/1.创建普通用户/create_user.md
浏览文件 @ ba97f6ea
......@@ -13,8 +13,11 @@ 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
```sql
create user 'john'@'192.168.7.42' identified by 'goods123' password expire;
create user 'john'@'192.168.7.42'
identified by 'goods123' password expire;
grant select on goods.* to 'john'@'192.168.7.42';
flush privileges;
```
......@@ -23,22 +26,31 @@ flush privileges;
### A
```sql
create user 'john'@'192.168.7.42' identified by 'goods123';
create user 'john'@'192.168.7.42'
identified by 'goods123';
grant select on goods.* to 'john'@'192.168.7.42';
flush privileges;
```
### B
```sql
create user 'john'@'192.168.7.42' identified by 'goods123';
grant usage on goods.* to 'john'@'192.168.7.42';
create user 'john'@'192.168.7.42'
identified by 'goods123';
grant usage on
goods.* to 'john'@'192.168.7.42';
flush privileges;
```
### C
```sql
create user 'john'@'192.168.7.42' identified by 'goods123' on database goods;
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/11.用户和权限/1.创建普通用户/create_user_desc.md
浏览文件 @ ba97f6ea
......@@ -22,31 +22,21 @@ IDENTIFIED BY '@Binghe123456';
### A
```
可以使用GRANT来创建用户
```
### B
```
可以使用CREATE USER语句来创建用户
```
### C
```
CREATE USER 'binghe'@'localhost';
创建用户名为binghe的MySQL用户，其主机名为localhost。
```
### D
```
使用GRANT语句创建用户，不仅可以添加用户，而且还能为用户赋予相应的权限。
```
### E
```
使用CREATE USER语句创建用户时，只是在mysql数据库下的user数据表中添加了一条记录，并没有为用户授权。
```
\ No newline at end of file
data/2.MySQL中阶/11.用户和权限/7.限制用户使用资源/limit_action.md
浏览文件 @ ba97f6ea
......@@ -12,7 +12,8 @@ Joe 需要限制数据分析组（role analysis）的用户, 每小时查询次
## 答案
```sql
alter user analysis with MAX_QUERIES_PER_HOUR 10000;
alter user analysis
with MAX_QUERIES_PER_HOUR 10000;
```
## 选项
......@@ -20,24 +21,28 @@ alter user analysis with MAX_QUERIES_PER_HOUR 10000;
### A
```sql
set user analysis with MAX_QUERIES_PER_HOUR 10000;
set user analysis
with MAX_QUERIES_PER_HOUR 10000;
```
### B
```sql
alter role analysis with MAX_QUERIES_PER_HOUR 10000;
alter role analysis
with MAX_QUERIES_PER_HOUR 10000;
```
### C
```sql
alter role analysis with MAX_QUERIES_PER_HOUR=10000;
alter role analysis
with MAX_QUERIES_PER_HOUR=10000;
```
### D
```sql
alter user analysis set MAX_QUERIES_PER_HOUR 10000;
alter user analysis
set MAX_QUERIES_PER_HOUR 10000;
```
data/2.MySQL中阶/2.查询进阶/2. BETWEEN/between.md
浏览文件 @ ba97f6ea
......@@ -24,7 +24,10 @@ create table goods(
## 答案
```sql
SELECT * FROM goods HAVING price BETWEEN 1000 AND 2000;
SELECT *
FROM goods
HAVING price
BETWEEN 1000 AND 2000;
```
......@@ -33,18 +36,25 @@ SELECT * FROM goods HAVING price BETWEEN 1000 AND 2000;
### A
```sql
SELECT * FROM goods WHERE price BETWEEN 1000 AND 2000;
SELECT *
FROM goods
WHERE price
BETWEEN 1000 AND 2000;
```
### B
```sql
SELECT * FROM goods WHERE price >= 1000 AND price <= 2000;
SELECT *
FROM goods
WHERE price >= 1000 AND price <= 2000;
```
### C
```sql
SELECT * FROM goods WHERE not (price < 1000 or price > 2000);
SELECT *
FROM goods
WHERE not (price < 1000 or price > 2000);
```
data/2.MySQL中阶/2.查询进阶/2. BETWEEN/config.json
浏览文件 @ ba97f6ea
{
"node_id": "mysql-2296dbe96d584a52bd28a3ad5f655518",
"keywords": ["where"],
"keywords": [
"where"
],
"children": [],
"export": [
"between.json"
],
"keywords_must": [
["mysql", "between"]
[
"mysql",
"between"
]
],
"keywords_forbid": [],
"group": 1
......
data/2.MySQL中阶/2.查询进阶/4.DISTINCT/distinct.md
浏览文件 @ ba97f6ea
......@@ -26,7 +26,8 @@ create table goods(
## 答案
```sql
select count(distinct price) from goods;
select count(distinct price)
from goods;
```
## 选项
......@@ -34,23 +35,27 @@ select count(distinct price) from goods;
### A
```sql
select count(distinct *) from goods;
select count(distinct *)
from goods;
```
### B
```sql
select distinct count(price) from goods;
select distinct count(price)
from goods;
```
### C
```sql
select count(price) from goods;
select count(price)
from goods;
```
### D
```sql
select distinct price from goods;
select distinct price
from goods;
```
data/2.MySQL中阶/2.查询进阶/5.ORDER BY/order_by.md
浏览文件 @ ba97f6ea
......@@ -24,7 +24,9 @@ create table employee
## 答案
```sql
select id, name, dept, salary from employee order by dept, salary desc;
select id, name, dept, salary
from employee
order by dept, salary desc;
```
## 选项
......@@ -32,28 +34,38 @@ select id, name, dept, salary from employee order by dept, salary desc;
### A
```sql
select id, name, dept, salary from employee order by dept, salary;
select id, name, dept, salary
from employee
order by dept, salary;
```
### B
```sql
select id, name, dept, salary from employee order by dept desc, salary desc;
select id, name, dept, salary
from employee
order by dept desc, salary desc;
```
### C
```sql
select id, name, dept, salary from employee order by dept and salary desc;
select id, name, dept, salary
from employee
order by dept and salary desc;
```
### D
```sql
select id, name, dept, salary from employee order by dept, salary, id, name;
select id, name, dept, salary
from employee
order by dept, salary, id, name;
```
### E
```sql
select id, name, dept, salary from employee order by dept, salary desc;
select id, name, dept, salary
from employee
order by dept, salary desc;
```
data/2.MySQL中阶/2.查询进阶/6.UNION/config.json
浏览文件 @ ba97f6ea
{
"node_id": "mysql-b57b6c08f5f240c6a997284e4448f088",
"keywords": ["union"],
"keywords": [
"union"
],
"children": [],
"export": [
"union.json"
],
"keywords_must": [
["mysql", "union"]
[
"mysql",
"union"
]
],
"keywords_forbid": [],
"group": 1
......
data/2.MySQL中阶/2.查询进阶/6.UNION/union.md
浏览文件 @ ba97f6ea
......@@ -12,10 +12,10 @@ create table employee(
);
create table customer(
id int primary key auto_increment,
name varchar(256),
address varchar(1024),
level int
id int primary key auto_increment,
name varchar(256),
address varchar(1024),
level int
-- ignore more
)
......
data/2.MySQL中阶/2.查询进阶/8. 分页查询/paged.md
浏览文件 @ ba97f6ea
......@@ -25,7 +25,11 @@ create table orders
## 答案
```sql
select id, product_id, order_date, quantity, customer_id
select id,
product_id,
order_date,
quantity,
customer_id
from orders
where date = $1
offset $2 limit 100;
......@@ -36,7 +40,11 @@ offset $2 limit 100;
### 缺少 limit
```sql
select id, product_id, order_date, quantity, customer_id
select id,
product_id,
order_date,
quantity,
customer_id
from orders
where date = $1
offset $2;
......@@ -45,7 +53,11 @@ offset $2;
### 缺少 offset
```sql
select id, product_id, order_date, quantity, customer_id
select id,
product_id,
order_date,
quantity,
customer_id
from orders
where date = $1;
```
......@@ -53,7 +65,11 @@ where date = $1;
### 结构不对
```sql
select id, product_id, order_date, quantity, customer_id
select id,
product_id,
order_date,
quantity,
customer_id
from orders
where date = $1 and
offset $2 and limit 100;
......
data/2.MySQL中阶/3.内置函数/5.其它函数/convert.md
浏览文件 @ ba97f6ea
......@@ -18,7 +18,8 @@ select name from goods;
## 答案
```sql
select convert(name using 'gb18030') from goods;
select convert(name using 'gb18030')
from goods;
```
## 选项
......@@ -27,27 +28,31 @@ select convert(name using 'gb18030') from goods;
### A
```sql
select str(name, 'gb18303') from goods;
select str(name, 'gb18303')
from goods;
```
### B
```sql
select encode(decode(name, 'utf8mb4'), 'gb18303') from goods;
select encode(decode(name, 'utf8mb4'), 'gb18303')
from goods;
```
### C
```sql
select convert(name from 'utf8mb4' to 'gb18303') from goods;
select convert(name from 'utf8mb4' to 'gb18303')
from goods;
```
### D
```sql
select convert(name to 'gb18303') from goods;
select convert(name to 'gb18303')
from goods;
```
### E
......
data/2.MySQL中阶/4.聚合和分组/1. 计数/count.md
浏览文件 @ ba97f6ea
......@@ -17,7 +17,8 @@ mysql> select * from items;
当他执行
```sql
select count(*), count(item) from items;
select count(*), count(item)
from items;
```
会得到什么结果？
......
data/2.MySQL中阶/4.聚合和分组/2. 求和/sum.md
浏览文件 @ ba97f6ea
......@@ -4,14 +4,14 @@ Joe 想要得到 orders 表
```sql
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
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
);
```
......@@ -27,7 +27,9 @@ create table orders (
## 答案
```sql
select sum(total) from orders where deal and unit_price > 1000;
select sum(total)
from orders
where deal and unit_price > 1000;
```
## 选项
......@@ -35,17 +37,24 @@ select sum(total) from orders where deal and unit_price > 1000;
### A
```sql
select sum(total) from orders having deal and unit_price > 1000;
select sum(total)
from orders
having deal and unit_price > 1000;
```
### B
```sql
select sum(total) from orders group by deal having unit_price > 1000;
select sum(total)
from orders
group by deal
having unit_price > 1000;
```
### C
```sql
select sum(total) from orders order by deal and unit_price > 1000;
select sum(total)
from orders
order by 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
浏览文件 @ ba97f6ea
......@@ -24,7 +24,9 @@ create table employee
## 答案
```sql
select dept, min(salary) from employee group by dept;
select dept, min(salary)
from employee
group by dept;
```
## 选项
......@@ -32,17 +34,20 @@ select dept, min(salary) from employee group by dept;
### A
```sql
select dept, min(salary) from employee;
select dept, min(salary)
from employee;
```
### B
```sql
select dept, min(salary) from employee order by dept;
select dept, min(salary)
from employee order by dept;
```
### C
```sql
select dept, min(total) from employee;
select dept, min(total)
from employee;
```
\ No newline at end of file
data/2.MySQL中阶/4.聚合和分组/5. 平均值/avg.md
浏览文件 @ ba97f6ea
......@@ -24,7 +24,9 @@ create table employee
## 答案
```sql
select dept, avg(salary) from employee group by dept;
select dept, avg(salary)
from employee
group by dept;
```
## 选项
......@@ -32,17 +34,22 @@ select dept, avg(salary) from employee group by dept;
### A
```sql
select dept, avg(salary) from employee;
select dept, avg(salary)
from employee;
```
### B
```sql
select dept, avg(dept) from employee group by dept;
select dept, avg(dept)
from employee
group by dept;
```
### C
```sql
select dept, avg(salary) from employee group by salary;
select dept, avg(salary)
from employee
group by salary;
```
data/2.MySQL中阶/4.聚合和分组/5. 平均值/config.json
浏览文件 @ ba97f6ea
{
"node_id": "mysql-11462fccf9d24d17a372d5c60af90f54",
"keywords": ["avg", "平均值"],
"keywords": [
"avg",
"平均值"
],
"children": [],
"export": [
"avg.json"
......
data/2.MySQL中阶/4.聚合和分组/6.HAVING/config.json
浏览文件 @ ba97f6ea
......@@ -6,7 +6,10 @@
"having.json"
],
"keywords_must": [
["mysql", "having"]
[
"mysql",
"having"
]
],
"keywords_forbid": [],
"group": 1
......
data/2.MySQL中阶/4.聚合和分组/6.HAVING/having.md
浏览文件 @ ba97f6ea
......@@ -24,7 +24,10 @@ create table employee
## 答案
```sql
select dept from employee group by dept having sum(salary) > 100000;
select dept
from employee
group by dept
having sum(salary) > 100000;
```
## 选项
......@@ -32,25 +35,36 @@ select dept from employee group by dept having sum(salary) > 100000;
### A
```sql
select dept from employee group by dept where sum(salary) > 100000;
select dept
from employee
group by dept where sum(salary) > 100000;
```
### B
```sql
select dept from employee where sum(salary) > 100000 group by dept;
select dept
from employee
where sum(salary) > 100000
group by dept;
```
### C
```sql
select dept from employee where sum(salary) > 100000 order by dept;
select dept
from employee
where sum(salary) > 100000
order by dept;
```
### D
```sql
select dept from employee group by dept where sum(salary) > 100000;
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
浏览文件 @ ba97f6ea
......@@ -48,7 +48,8 @@ having salary > max(salary)
```sql
select l.id, l.name, l.dept, l.salary
from employee as l
join employee as r on l.salary > max(r.salary)
join employee as r
on l.salary > max(r.salary)
where r.dept = 'sale'
group by r.dept
```
......@@ -58,7 +59,9 @@ group by r.dept
```sql
select id, name, dept, salary
from employee
having salary > (select max(salary) from employee where dept = 'sale')
having salary > (select max(salary)
from employee
where dept = 'sale')
```
......
data/2.MySQL中阶/5.子查询/2. ANY/any.md
浏览文件 @ ba97f6ea
......@@ -25,7 +25,9 @@ create table employee(
```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)
where o.salary < any(select salary
from employee as i
where i.dept=o.dept)
```
## 选项
......@@ -35,7 +37,8 @@ where o.salary < any(select salary from employee as i where i.dept=o.dept)
```sql
select id, name, dept, salary
from employee as o
join employee as i on o.dept = i.dept and o.salary < i.salary
join employee as i on
o.dept = i.dept and o.salary < i.salary
```
### B
......@@ -43,7 +46,8 @@ join employee as i on o.dept = i.dept and o.salary < i.salary
```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
left join employee as i on
o.dept = i.dept and o.salary < i.salary
where i.id is null;
```
......@@ -52,6 +56,7 @@ where i.id is null;
```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
left join employee as i
on o.dept = i.dept and o.salary < i.salary
where i.id is not null;
```
\ No newline at end of file
data/2.MySQL中阶/5.子查询/3.ALL/all.md
浏览文件 @ ba97f6ea
......@@ -25,7 +25,10 @@ create table employee(
```sql
select id, name, dept
from employee as o
where 'assistant' != all(select post from employee as i where o.dept = i.dept);
where 'assistant' !=
all(select post
from employee as i
where o.dept = i.dept);
```
## 选项
......@@ -35,7 +38,10 @@ where 'assistant' != all(select post from employee as i where o.dept = i.dept);
```sql
select id, name, dept
from employee as o
where 'assistant' = all(select post from employee as i where o.dept = i.dept);
where 'assistant' =
all(select post
from employee as i
where o.dept = i.dept);
```
### B
......@@ -43,14 +49,19 @@ where 'assistant' = all(select post from employee as i where o.dept = i.dept);
```sql
select id, name, dept
from employee as o
where 'assistant' != all(select post from employee as i where o.dept = i.dept);
where 'assistant' !=
all(select post
from employee as i
where o.dept = i.dept);
```
### C
```sql
select id, name, dept
from employee as o
where 'assistant' != all(select post from employee as i);
where 'assistant' !=
all(select post
from employee as i);
```
### D
......@@ -58,5 +69,8 @@ where 'assistant' != all(select post from employee as i);
```sql
select id, name, dept
from employee as o
where 'assistant' != ANY(select post from employee as i where o.dept = i.dept);
where 'assistant' !=
ANY(select post
from employee as i
where o.dept = i.dept);
```
\ No newline at end of file
data/2.MySQL中阶/5.子查询/4.EXISTS/exists.md
浏览文件 @ ba97f6ea
......@@ -26,7 +26,10 @@ create table employee(
```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');
where not exists(
select *
from employee as i
where o.dept = i.dept and post='assistant');
```
## 选项
......@@ -36,14 +39,19 @@ where not exists(select * from employee as i where o.dept = i.dept and post='ass
```sql
select id, name, dept
from employee as o
where exists(select * from employee as i where o.dept = i.dept and post='assistant');
where exists(
select *
from employee as i
where o.dept = i.dept and post='assistant');
```
### B
```sql
select id, name, dept
from employee as o
where 'assistant' != exists(select post from employee as i);
where 'assistant' != exists(
select post
from employee as i);
```
### C
......@@ -51,5 +59,8 @@ where 'assistant' != exists(select post from employee as i);
```sql
select id, name, dept
from employee as o
where 'assistant' = not exists(select post from employee as i where o.dept = i.dept);
where 'assistant' = not exists(
select post
from employee as i
where o.dept = i.dept);
```
\ No newline at end of file
data/2.MySQL中阶/5.子查询/5. IN/in.md
浏览文件 @ ba97f6ea
......@@ -43,7 +43,9 @@ where dept in (select 'dev', 'hr');
```sql
select id, dept, name, post
from employee
where dept in (select * from 'dev', 'hr');
where dept in
(select *
from 'dev', 'hr');
```
### C
......
data/2.MySQL中阶/5.子查询/6. 列子查询/in_column.md
浏览文件 @ ba97f6ea
......@@ -24,10 +24,10 @@ create table employee
## 答案
```sql
select distinct(dept) as dept,
(select count(*)
from employee as i
where i.dept = o.dept) as emp
select distinct(dept) as dept,
(select count(*)
from employee as i
where i.dept = o.dept) as emp
from employee as o;
```
......@@ -36,28 +36,28 @@ from employee as o;
### A
```sql
select distinct(dept) as dept,
(select count(*)
from employee as i) as emp
select distinct(dept) as dept,
(select count(*)
from employee as i) as emp
from employee as o;
```
### B
```sql
select distinct(dept) as dept,
(select count(*)
from employee
where dept = dept) as emp
select distinct(dept) as dept,
(select count(*)
from employee
where dept = dept) as emp
from employee
```
### C
```sql
select dept as dept,
(select count(*)
from employee as i
where i.dept = o.dept) as emp
select dept as dept,
(select count(*)
from employee as i
where i.dept = o.dept) as emp
from employee as o
```
\ No newline at end of file
data/2.MySQL中阶/6.连接查询/2. LEFT JOIN/left_join.md
浏览文件 @ ba97f6ea
......@@ -34,8 +34,11 @@ Joe 想要列出所有的部门，如果这个部门有部门助理（post 为 `
```sql
select d.id, d.name, e.name as assistant
from department as d
left join employee as e on e.dept = d.id
where e.post = 'assistant'
left join (select name, dept_id
from employee
where post='assistant') as e on e.dept_id = d.id
```
## 选项
......
data/2.MySQL中阶/6.连接查询/3. RIGHT JOIN/right_join.md
浏览文件 @ ba97f6ea
......@@ -46,7 +46,7 @@ where d.id is null;
```sql
select e.id, e.name, e.dept
from employee as e
right join department as d on d.id = e.dept
right join department as d on d.id = e.dept
where e.id is null;
```
......@@ -55,7 +55,7 @@ where e.id is null;
```sql
select e.id, e.name, e.dept
from employee as e
right join department as d on d.id = e.dept
right join department as d on d.id = e.dept
where d.id is null;
```
......
data/2.MySQL中阶/7. 索引/2.创建索引/config.json
浏览文件 @ ba97f6ea
{
"node_id": "mysql-fe65d5c615ad40f8ac056cc654f2d788",
"keywords": ["create index", "创建索引"],
"keywords": [
"create index",
"创建索引"
],
"children": [],
"export": [
"create_index.json"
......
data/2.MySQL中阶/7. 索引/2.创建索引/create_index.md
浏览文件 @ ba97f6ea
......@@ -27,7 +27,8 @@ create table goods(
## 答案
```sql
create index idx_goods_category on goods(category_id);
create index idx_goods_category
on goods(category_id);
```
## 选项
......@@ -35,17 +36,20 @@ create index idx_goods_category on goods(category_id);
### A
```sql
create unique index idx_goods_category on goods(category_id);
create unique index idx_goods_category
on goods(category_id);
```
### B
```sql
create index idx_goods_category on goods(name);
create index idx_goods_category
on goods(name);
```
### C
```sql
alter table goods add unique index (category_id);
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
浏览文件 @ ba97f6ea
......@@ -20,7 +20,8 @@ show index from goods;
查看 goods 表的索引（假设查到是 idx_goods_category），然后执行
```sql
alter table goods drop index idx_goods_category;
alter table goods
drop index idx_goods_category;
```
## 选项
......@@ -36,7 +37,8 @@ show index from goods;
查看 goods 表的索引（假设查到是 idx_goods_category），然后执行
```sql
alter table goods delete index idx_goods_category;
alter table goods
delete index idx_goods_category;
```
### B
......@@ -50,7 +52,8 @@ show index from goods;
查看 goods 表的索引（假设查到是 idx_goods_category），然后执行
```sql
alter table goods remove index idx_goods_category;
alter table goods
remove index idx_goods_category;
```
### C
......@@ -64,7 +67,8 @@ show index from goods;
查看 goods 表的索引（假设查到是 idx_goods_category），然后执行
```sql
alter table goods drop idx_goods_category;
alter table goods
drop idx_goods_category;
```
......
data/3.MySQL高阶/1.深入索引/1.唯一索引/unique.md
浏览文件 @ ba97f6ea
......@@ -25,7 +25,8 @@ 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
```sql
alter table goods add unique index (category_id, name);
alter table goods
add unique index (category_id, name);
```
## 选项
......@@ -33,17 +34,20 @@ alter table goods add unique index (category_id, name);
### A
```sql
alter table goods add index (category_id, name);
alter table goods
add index (category_id, name);
```
### B
```sql
alter table goods add unique index (category_id + name);
alter table goods
add unique index (category_id + name);
```
### C
```sql
alter table goods add unique index (concat(category_id, name));
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/config.json
浏览文件 @ ba97f6ea
......@@ -7,7 +7,12 @@
"export": [
"total_index.json"
],
"keywords_must": [["mysql", "全值匹配"]],
"keywords_must": [
[
"mysql",
"全值匹配"
]
],
"keywords_forbid": [],
"group": 2
}
\ No newline at end of file
data/3.MySQL高阶/1.深入索引/2.全值匹配/total_index.md
浏览文件 @ ba97f6ea
......@@ -25,7 +25,8 @@ create table goods(
## 答案
```sql
alter table goods add index (name, price);
alter table goods
add index (name, price);
```
## 选项
......@@ -39,11 +40,14 @@ alter table goods add index (name, price);
建立一个计算字段：
```sql
alter table goods add summary varchar(1024) generated always as (concat(name, '(', 0.5, ')'));
alter table goods
add summary varchar(1024)
generated always as (concat(name, '(', 0.5, ')'));
```
### C
```sql
alter table goods add index (concat(name, price));
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
浏览文件 @ ba97f6ea
......@@ -29,7 +29,12 @@ Joe 发现有大量查询 `select id, category_id, name, price from goods where
将该查询改写为
```sql
select id, category_id, name, price from goods where category_id=? and name=?;
select id,
category_id,
name,
price
from goods
where category_id=? and name=?;
```
## 选项
......@@ -39,7 +44,12 @@ select id, category_id, name, price from goods where category_id=? and name=?;
将该查询改写为
```sql
select id, category_id, name, price from goods where category_id and name= (?, ?);
select id,
category_id,
name,
price
from goods
where category_id and name= (?, ?);
```
### B
......@@ -47,7 +57,12 @@ select id, category_id, name, price from goods where category_id and name= (?, ?
将该查询改写为
```sql
select id, category_id, name, price from goods where not (category_id !=? or name != ?);
select id,
category_id,
name,
price
from goods
where not (category_id !=? or name != ?);
```
### C
......@@ -55,6 +70,11 @@ select id, category_id, name, price from goods where not (category_id !=? or nam
将该查询改写为
```sql
select id, category_id, name, price from goods where not (category_id !=?) and not (name != ?);
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
浏览文件 @ ba97f6ea
......@@ -14,7 +14,19 @@ create table goods(
)
```
现有大量查询 `select id, category_id, name, price, stock from goods where stock=? and category_id=? and name like ?`，
现有大量查询
```sql
select
id,
category_id,
name,
price,
stock
from goods
where stock=?
and category_id=?
and name like ?`，
```
Joe 应该如何优化？
<hr/>
......@@ -27,7 +39,8 @@ Joe 应该如何优化？
## 答案
```sql
alter table goods add index (stock, category_id, name);
alter table goods
add index (stock, category_id, name);
```
## 选项
......@@ -35,17 +48,20 @@ alter table goods add index (stock, category_id, name);
### A
```sql
alter table goods add index (stock and category_id and name);
alter table goods
add index (stock and category_id and name);
```
### B
```sql
alter table goods add index (concat(stock, category_id, name));
alter table goods
add index (concat(stock, category_id, name));
```
### C
```sql
alter table goods add index (stock + category_id + name);
alter table goods
add index (stock + category_id + name);
```
data/3.MySQL高阶/1.深入索引/5.空间索引/geo_index.md
浏览文件 @ ba97f6ea
......@@ -22,8 +22,10 @@ create table shop (
## 答案
```sql
alter table shop modify location GEOMETRY not null;
alter table shop add INDEX geo_index(location);
alter table shop
modify location GEOMETRY not null;
alter table shop
add INDEX geo_index(location);
```
## 选项
......@@ -31,25 +33,31 @@ alter table shop add INDEX geo_index(location);
### A
```sql
alter table shop add INDEX geo_index(location);
alter table shop
add INDEX geo_index(location);
```
### B
```sql
alter table shop add INDEX location;
alter table shop
add INDEX location;
```
### C
```sql
alter table shop modify location GEOMETRY not null;
alter table shop add INDEX location;
alter table shop
modify location GEOMETRY not null;
alter table shop
add INDEX location;
```
### D
```sql
alter table shop modify location GEOMETRY not null;
alter table shop add INDEX location;
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
浏览文件 @ ba97f6ea
......@@ -22,7 +22,8 @@ create table shop (
## 答案
```sql
alter table shop add fulltext(description);
alter table shop
add fulltext(description);
```
## 选项
......@@ -30,17 +31,20 @@ alter table shop add fulltext(description);
### A
```sql
alter table shop add index fulltext(description);
alter table shop
add index fulltext(description);
```
### B
```sql
alter table shop create fulltext(description);
alter table shop
create fulltext(description);
```
### C
```sql
alter table shop alter description add fulltext(description);
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/config.json
浏览文件 @ ba97f6ea
{
"node_id": "mysql-c57e1195b0914cd38798ce029156ec87",
"keywords": ["invisible", "visible", "隐藏索引"],
"keywords": [
"invisible",
"visible",
"隐藏索引"
],
"children": [],
"export": [
"invisible.json"
......
data/3.MySQL高阶/1.深入索引/7.隐藏索引/invisible.md
浏览文件 @ ba97f6ea
......@@ -28,13 +28,15 @@ Joe 应该怎么做？
先执行
```sql
alter table shop alter index description invisible ;
alter table shop
alter index description invisible ;
```
将索引隐藏，观察确认没有影响后再执行
```sql
alter table shop drop index description;
alter table shop
drop index description;
```
删除。
......@@ -47,7 +49,8 @@ alter table shop drop index description;
先备份 shop 表，然后执行
```sql
alter table shop drop index description;
alter table shop
drop index description;
```
删除，有问题的话从备份文件恢复。
......@@ -60,13 +63,15 @@ alter table shop drop index description;
先执行
```sql
alter table shop alter index description invisible ;
alter table shop
alter index description invisible ;
```
将索引隐藏，确认后再执行
```sql
alter table shop alter index description visible ;
alter table shop
alter index description visible ;
```
恢复索引可见。
\ No newline at end of file
data/3.MySQL高阶/1.深入索引/8.函数和表达式索引/daily_payment.md
浏览文件 @ ba97f6ea
......@@ -40,7 +40,8 @@ mysql> desc payment;
建立表达式索引
```sql
alter table payment add index idx_payment_date((date(payment_date)));
alter table payment
add index idx_payment_date((date(payment_date)));
```
## 选项
......@@ -50,7 +51,8 @@ alter table payment add index idx_payment_date((date(payment_date)));
建立视图
```sql
create view view_daily_payment as select date(payment_date) as day, amount from payment;
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
......@@ -75,7 +77,8 @@ create index idx_payment_date on payment(payment_date);
建立计算列
```sql
alter table payment add day date generated always as (date(payment_date)) stored;
alter table payment add day date
generated always as (date(payment_date)) stored;
```
然后使用它改写查询
......
data/3.MySQL高阶/2.SQL高级技巧/1.CTE和递归查询/continuous.md
浏览文件 @ ba97f6ea
......@@ -28,13 +28,14 @@ create table orders
## 答案
```sql
with recursive r(id) as (select id
from orders
where id = $1
union
select d.id
from orders as d
join r on d.id = r.id + 1)
with recursive r(id) as (
select id
from orders
where id = $1
union
select d.id
from orders as d
join r on d.id = r.id + 1)
select orders.id, content
from orders
join r on orders.id = r.id;
......@@ -50,8 +51,8 @@ from orders
```sql
select data.id, content
from orders
join orders as r on orders.id = r.id - 1
from orders
join orders as r on orders.id = r.id - 1
where id = $1;
```
......@@ -60,7 +61,10 @@ where id = $1;
```sql
select id, content
from orders
where id in (select id from orders where id = id + 1);
where id in (
select id
from orders
where id = id + 1);
```
### D
......
data/3.MySQL高阶/2.SQL高级技巧/2.Window Function/salary.md
浏览文件 @ ba97f6ea
......@@ -25,7 +25,13 @@ create table employee
```sql
select id, name, dept, salary
from (select id, name, dept, salary, rank() over (partition by dept order by salary desc) as r
from (select id,
name,
dept,
salary,
rank() over (
partition by dept
order by salary desc) as r
from employee) as t
where r <= 5;
```
......@@ -58,16 +64,23 @@ where count(r.id) <= 5;
```sql
select l.id, l.name, l.dept, l.salary
from employee as l
join (select max(salary, 5) as salary, dept
from employee
group by dept) as r
on l.dept = r.dept and l.salary = r.salary
join (
select max(salary, 5) as salary, dept
from employee
group by dept) as r
on l.dept = r.dept and l.salary = r.salary
```
### 结构错误
```sql
select id, name, dept, salary, rank() over (partition by dept order by salary desc) as r
select id,
name,
dept,
salary,
rank() over (
partition by dept
order by salary desc) as r
from employee
where r <= 5;
```
......@@ -75,7 +88,13 @@ where r <= 5;
### 结构错误
```sql
select id, name, dept, salary, rank() as r over (partition by dept order by salary desc)
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 /config.json
浏览文件 @ ba97f6ea
......@@ -9,7 +9,9 @@
"export": [
"pivot.json"
],
"keywords_must": ["mysql"],
"keywords_must": [
"mysql"
],
"keywords_forbid": [],
"group": 1
}
\ No newline at end of file
data/3.MySQL高阶/2.SQL高级技巧/3.透视表 /pivot.md
浏览文件 @ ba97f6ea
......@@ -25,18 +25,30 @@ create index on sales(created_at);
```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,
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
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;
......@@ -78,18 +90,30 @@ group by sku_id, extract(month from created_at);
```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,
sum(amount having extract(month from created_at) = 3) as Mar,
sum(amount having extract(month from created_at) = 4) as Apr,
sum(amount having extract(month from created_at) = 5) as May,
sum(amount having extract(month from created_at) = 6) as June,
sum(amount having extract(month from created_at) = 7) as July,
sum(amount having extract(month from created_at) = 8) as Aug,
sum(amount having extract(month from created_at) = 9) as Sept,
sum(amount having extract(month from created_at) = 10) as Oct,
sum(amount having extract(month from created_at) = 11) as Nov,
sum(amount having extract(month from created_at) = 12) as Dec
sum(amount having
extract(month from created_at) = 1) as Jan,
sum(amount having
extract(month from created_at) = 2) as Feb,
sum(amount having
extract(month from created_at) = 3) as Mar,
sum(amount having
extract(month from created_at) = 4) as Apr,
sum(amount having
extract(month from created_at) = 5) as May,
sum(amount having
extract(month from created_at) = 6) as June,
sum(amount having
extract(month from created_at) = 7) as July,
sum(amount having
extract(month from created_at) = 8) as Aug,
sum(amount having
extract(month from created_at) = 9) as Sept,
sum(amount having
extract(month from created_at) = 10) as Oct,
sum(amount having
extract(month from created_at) = 11) as Nov,
sum(amount having
extract(month from created_at) = 12) as Dec
from sales
where created_at between '2020-01-01'::timestamp and '2021-01-01'::timestamp
group by sku_id, extract(month from created_at);
......
data/3.MySQL高阶/2.SQL高级技巧/4.Double Not Exists/DoubleNotExists.md
浏览文件 @ ba97f6ea
......@@ -46,14 +46,14 @@ Joe 想要找出参与了所有投标的企业（有围标嫌疑），那么这
select *
from company
where not exists(
select *
from invitation
where not exists(
select *
from bids
where invitation.id = bids.invitation_id
and bids.company_id = company.id
)
select *
from invitation
where not exists(
select *
from bids
where invitation.id = bids.invitation_id
and bids.company_id = company.id
)
)
```
......@@ -82,7 +82,9 @@ where id = any (select company_id
```sql
select *
from company
where company.id in (select distinct company_id from bids)
where company.id in (
select distinct company_id
from bids)
```
### D
......@@ -91,8 +93,8 @@ where company.id in (select distinct company_id from bids)
select *
from company
where exists(
select *
from bids
where bids.company_id = company.id
)
select *
from bids
where bids.company_id = company.id
)
```
\ No newline at end of file
data/3.MySQL高阶/2.SQL高级技巧/4.Double Not Exists/config.json
浏览文件 @ ba97f6ea
......@@ -9,7 +9,9 @@
"export": [
"DoubleNotExists.json"
],
"keywords_must": ["mysql"],
"keywords_must": [
"mysql"
],
"keywords_forbid": [],
"groups": 2
}
\ No newline at end of file
data/3.MySQL高阶/2.SQL高级技巧/5.写入和冲突/score.md
浏览文件 @ ba97f6ea
......@@ -22,7 +22,8 @@ create table book_in(
## 答案
```sql
insert into book_in(login, score) values ($1, $2) on DUPLICATE KEY update score=$2;
insert into book_in(login, score)
values ($1, $2) on DUPLICATE KEY update score=$2;
```
## 选项
......
data/3.MySQL高阶/3.过程化编程/5. 游标/cursor.md
浏览文件 @ ba97f6ea
......@@ -74,7 +74,9 @@ end;
create procedure make_trade()
begin
DECLARE done INT DEFAULT FALSE;
declare cur_orders cursor for select id, price, item_id, amount from orders order by id limit 1000;
declare cur_orders cursor for
select id, price, item_id, amount
from orders order by id limit 1000;
declare order_id, item_id, amount INT;
declare price decimal(12, 4);
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
......@@ -100,7 +102,11 @@ end;
```sql
create procedure make_trade()
begin
declare cur_orders cursor for select id, price, item_id, amount from orders order by id limit 1000;
declare cur_orders cursor for
select id, price, item_id, amount
from orders
order by id
limit 1000;
declare order_id, item_id, amount INT;
declare price decimal(12, 4);
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
......@@ -122,7 +128,11 @@ end;
create procedure make_trade()
begin
DECLARE done INT DEFAULT FALSE;
declare cur_orders cursor for select id, price, item_id, amount from orders order by id limit 1000;
declare cur_orders cursor for
select id, price, item_id, amount
from orders
order by id
limit 1000;
declare order_id, item_id, amount INT;
declare price decimal(12, 4);
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
......@@ -143,7 +153,11 @@ end;
create procedure make_trade()
begin
DECLARE done INT DEFAULT FALSE;
declare cur_orders cursor for select id, price, item_id, amount from orders order by id limit 1000;
declare cur_orders cursor for
select id, price, item_id, amount
from orders
order by id
limit 1000;
declare order_id, item_id, amount INT;
declare price decimal(12, 4);
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
......
data/3.MySQL高阶/3.过程化编程/5. 游标/cursor_desc.md
浏览文件 @ ba97f6ea
......@@ -19,24 +19,16 @@
### A
```
"DECLARE 游标名字 CURSOR FOR 查询语句;" 用来声明游标
```
### B
```
定义好游标之后，需要使用"OPEN 游标名;"来打开游标
```
### C
```
游标使用有需要关闭"CLOSE 游标名;"
```
### D
```
游标就像指针一样，可以定位操作查询的数据
```
\ No newline at end of file
data/3.MySQL高阶/4.设计优化/1.生成列/generated.md
浏览文件 @ ba97f6ea
......@@ -30,7 +30,8 @@ column_name data_type [GENERATED ALWAYS] AS (expression)
## 答案
```sql
alter table points add modulus double generated always as (sqrt(x*x + y*y));
alter table points add modulus double
generated always as (sqrt(x*x + y*y));
```
## 选项
......@@ -38,17 +39,20 @@ alter table points add modulus double generated always as (sqrt(x*x + y*y));
### A
```sql
create generated modulus on table points as (sqrt(x*x + y*y));
create generated modulus
on table points as (sqrt(x*x + y*y));
```
### B
```sql
alter table points add modulus generated always as (sqrt(x*x + y*y));
alter table points
add modulus generated always as (sqrt(x*x + y*y));
```
### C
```sql
alter table points add modulus float generated sqrt(x*x + y*y);
alter table points
add modulus float generated sqrt(x*x + y*y);
```
data/3.MySQL高阶/4.设计优化/4.增加中间表/daily_payment2.md
浏览文件 @ ba97f6ea
......@@ -38,26 +38,35 @@ group by date(payment_date);
建立中间表并建立索引。
```postgresql
create table daily_payment(day date primary key , amount decimal(12, 4));
create table daily_payment(
day date primary key ,
amount decimal(12, 4));
insert into daily_payment(day, amount)
select payment_date::date as day, sum(amount) as amount from payment group by day;
select payment_date::date as day,
sum(amount) as amount
from payment group by day;
```
使用
```sql
select day, amount from view_daily_payment where day between $1 and $2;
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
```sql
insert into daily_payment(day, amount)
select date(payment_date) as day, sum(amount) as amount
select date(payment_date) as day,
sum(amount) as amount
from payment
where date(payment_date) between DATE_SUB(CURDATE(), INTERVAL 2 DAY) and DATE_SUB(CURDATE(), INTERVAL 1 DAY)
where date(payment_date)
between DATE_SUB(CURDATE(), INTERVAL 2 DAY)
and DATE_SUB(CURDATE(), INTERVAL 1 DAY)
group by day;
```
......@@ -69,7 +78,8 @@ group by day;
在 payment_date 列上建立索引
```sql
create index idx_payment_date on payment(payment_date);
create index idx_payment_date on
payment(payment_date);
```
### 不会优化 sum
......@@ -77,7 +87,8 @@ create index idx_payment_date on payment(payment_date);
建立计算列
```sql
alter table payment add day date generated always as ( payment_date::date ) stored
alter table payment add day date
generated always as ( payment_date::date ) stored
```
然后使用它改写查询
......@@ -94,7 +105,8 @@ group by day;
建立表达式索引
```sql
create index idx_payment_day on payment((date(payment_date)));
create index idx_payment_day
on payment((date(payment_date)));
```
### 不做物化，对查询速度不会有显著改善
......@@ -102,7 +114,8 @@ create index idx_payment_day on payment((date(payment_date)));
建立视图
```sql
create view view_daily_payment as select date(payment_date) as day, amount from payment;
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
......
data/3.MySQL高阶/5.运维与架构/6.复制过滤器/filter.md
浏览文件 @ ba97f6ea
......@@ -84,7 +84,8 @@ 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
```sql
CHANGE REPLICATION FILTER REPLICATE_IGNORE_DB=(goods, auth);
CHANGE REPLICATION FILTER
REPLICATE_IGNORE_DB=(goods, auth);
```
### J
......@@ -108,7 +109,8 @@ 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
```sql
CHANGE REPLICATION FILTER REPLICATE_DO_TABLE=( goods.goods,goods.orders);
CHANGE REPLICATION FILTER
REPLICATE_DO_TABLE=( goods.goods,goods.orders);
```
### M
......@@ -124,7 +126,8 @@ 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
```sql
CHANGE REPLICATION FILTER REPLICATE_WILD_DO_TABLE =( goods.t_%);
CHANGE REPLICATION FILTER
REPLICATE_WILD_DO_TABLE =( goods.t_%);
```
### P
......@@ -140,7 +143,8 @@ 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
```sql
CHANGE REPLICATION FILTER REPLICATE_ IGNORE_TABLE=( goods.orders,goods.trade);
CHANGE REPLICATION FILTER
REPLICATE_ IGNORE_TABLE=( goods.orders,goods.trade);
```
......@@ -157,7 +161,8 @@ 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
```sql
CHANGE REPLICATION FILTER REPLICATE_WILD_DO_TABLE =( goods.o_%);
CHANGE REPLICATION FILTER
REPLICATE_WILD_DO_TABLE =( goods.o_%);
```
### S
......
data/3.MySQL高阶/6.查询优化/3. EXPLAIN/explain.md
浏览文件 @ ba97f6ea
......@@ -3,13 +3,14 @@
Joe 从交易服务中发现了一些高频查询和慢查询，例如
```sql
with recursive r(id) as (select id
from orders
where id = $1
union
select d.id
from orders as d
join r on d.id = r.id + 1)
with recursive r(id) as (
select id
from orders
where id = $1
union
select d.id
from orders as d
join r on d.id = r.id + 1)
select orders.id, content
from orders
join r on orders.id = r.id;
......@@ -29,13 +30,14 @@ from orders
在测试库使用
```sql
explain with recursive r(id) as (select id
from orders
where id = $1
union
select d.id
from orders as d
join r on d.id = r.id + 1)
explain with recursive r(id) as (
select id
from orders
where id = $1
union
select d.id
from orders as d
join r on d.id = r.id + 1)
select orders.id, content
from orders
join r on orders.id = r.id;
......@@ -44,13 +46,14 @@ from orders
进行剖分，对于需要了解详细执行计划的使用
```sql
explain analyze with recursive r(id) as (select id
from orders
where id = 100
union
select d.id
from orders as d
join r on d.id = r.id + 1)
explain analyze with recursive r(id) as (
select id
from orders
where id = 100
union
select d.id
from orders as d
join r on d.id = r.id + 1)
select orders.id
from orders
join r on orders.id = r.id;
......@@ -73,13 +76,14 @@ from orders
使用
```sql
analyze with recursive r(id) as (select id
from orders
where id = 100
union
select d.id
from orders as d
join r on d.id = r.id + 1)
analyze with recursive r(id) as (
select id
from orders
where id = 100
union
select d.id
from orders as d
join r on d.id = r.id + 1)
select orders.id
from orders
join r on orders.id = r.id;
......
data/tree.json
浏览文件 @ ba97f6ea
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