一、介绍
在MySQL管理软件中，可以通过SQL语句中的DML语言来实现数据的操作，包括
- 使用INSERT实现数据的插入
- UPDATE实现数据的更新
- 使用DELETE实现数据的删除
- 使用SELECT查询数据。
二、插入数据INSERT
INSERT into info values(1,‘田硕‘,‘男‘); INSERT into info(id,NAMES) values(2,‘田硕‘); INSERT into info(id,NAMES) values(3,‘田硕‘),(4,‘田硕‘),(5,‘田硕‘); NSERT into info(names,sex) select nameS,sex from info ;
三、更新操作UPDATE
update info set sex = ‘女‘, names = ‘田硕‘ where id=5;
四、删除操作DELETE
DELETE from info where id = ‘11‘; -- 删除指定数据 DELETE from info; -- 删除整张表中所有的数据（一行一行删） TRUNCATE info; -- 清空整张表（直接都删，比delete快）
五、查询操作DELECT
5.1 简单查询
select * from person; -- 查询所有 select name,SEX from person; -- 按指定字段查询 select name,SEX as‘性别‘ from person; -- as 表示为字段起别名 select salary+200 from person; -- 可以进行数据列运算 select DISTINCT age,name FROM person; -- 去重复查询
5.2 条件查询
1.运算符
select * FROM person WHERE age >20; select * FROM person WHERE age <=20; select * FROM person WHERE age <>20;（也是不等于） select * FROM person WHERE age !=20;
2.关键字
select * FROM person where dept_id is null; select * FROM person where dept_id is not null; select * FROM person where name = ‘abc‘;
3.逻辑运算符 and or
select * from person where age = 28 and salary =53000; select * from person where age = 23 or salary =2000; select * from person where not(age = 28 and salary =53000);
5.3 区间查询
select * from person where age BETWEEN 18 and 20; ps: between...and 前后包含所指定的值 等价于 select * from person where salary >= 4000 and salary <= 8000;
5.4 集合查询
select * from person where id = 1 or id = 3 or id = 5; select * from person where id not in(1,3,5);
5.5 模糊查询
select * from person where name like ‘%e%‘; -- 包含指定参数 select * from person where name like ‘%e‘; -- 以什么结尾 select * from person where name like ‘e%‘; -- 以什么开头 select * from person where name like ‘__e%‘; -- _表示单个字符站位符 select * from person where name like ‘__‘;
5.6 排序查询
select * from person where age >30 ORDER BY salary desc; -- ASC正序 DESC倒序 select * from person ORDER BY CONVERT(name USING gbk);-- 中文排序
