MYSQL秘籍

Mysql语句复习

基础查询：
select * from employees

条件查询：
select * from employees where last_name=‘king’

模糊查询+排序查询：
select * from employees where last_name like ‘_e%’
order by length(email)desc

分组查询：
select max(salary)maxsalary from employees
group by department_id
having maxsalary > 3000

分组函数：
min max avg sum count

等值连接查询：
select* from employees e,departments d
where e.department_id = d.department_id

内连接查询：
select* from employees e inner join departmengts d
on e.department_id = d.department_id

单行子查询：
select * from employees
where department_id = (

)

多行子查询：
select * from employees
where department_id in (

)

分页查询：
select * from employees limit 10

插入数据：（两种方法）
insert into employees values (),(),()
或者
insert into employees
select …UNION
select …UNION
select …

更新数据：
update employees set …where

删除：
delete from employees where
（truncate ）不常用

快捷键：
window+D // 回到桌面
window+E //打开我的电脑
window+P //投影扩展屏