mysql简单的操作
增 insert
insert into t5(username) values('user1');
删 delete
删所有
delete from t5;
删一条
delete from t5 where id=10;
删除1<=id<=3
delete from t5 where id>=1 and id<=3;
删除id为1，3，5
delete from t5 where id=1 or id=3 or id=5;
delete from t5 where id in(1,5,3);
改 update
修改所有
update t5 set username='9';
修改一条
update t5 set username='9' where id=9;
修改某一条中的多个字段的数据(用逗号分开)
update t5 set username='9'，age=20 where id=9;
查 select
查所有
select * from t5;
查一条数据
select *from t5 where id=9;
