增
insert into user(username,password) values('1','11');
insert into user(username,password) values('2','22'),('3','33');
删
delete from user where id = 1;
改
update user set username='222',password='123456' where id = 1;
查
select [all|distinct] * from user
[where id=1]
[group by sex having 聚合后的字段>3]
[order by id asc|desc]
[limit n,m];
in(1,2,3)
between(100,200)
模糊查询 字段名 like '%a%';
select id,name,age,sex,concat(id,'号叫',name,',年龄',age,'岁') as user_info_str from user; //查询添加新字段
select id,name,age,if(sex=0,'man','woman') as sex from user; //查询结果sql里if判断
select
*
from
(select id,name,age,if(sex=0,'man','woman') as sex from user) aa
where aa.id=1; //查询再查询
select
id,
name,
age,
(case when sex=0 then 'man' when sex=1 then 'woman' else 'other' end ) as sex
from user; //case在sql里的语法
select group_concat(id) from user; // 字符串 “1,2,3,4,5,6”
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