mysql基本增删改查

发布时间 2023-11-26 01:06:28作者: adong搬砖
# 增 => insert into 表名 values(null,字段.....); //注意: 和数据库的表一一对应
insert into student values(null,'文渊','1234567','',3)
insert into student values(null,'文雯','123456','',3);
# 删 => delete from 表名 where id = ? //删除一般都是根据ID删除
delete from student where sid = 10;
delete from student where sid = 14;
# 修改 => update 表名 set 字段1 = 值1,字段2 = 值2 ... where id = ?
update student set susername = '锦jin',gender = '',clazzid = 1 where sid = 5;
update student set susername = '陈锦',gender = '' where sid = 6;
# 查询
## 基本查询 => select * from 表名
select * from student;
## where条件查询 => select * from 表名 where sid = ?
select * from student where sid = 1;
select * from student where gender = ''
select * from student where gender = ''
select * from student where clazzid = 3;
## 模糊查询 => select * from where susername like '% 锦 %'
select * from student where susername like '%锦%'
select * from student where susername like '%文%'
## 排序 select * from 表名 order by 字段 desc/asc  //desc:倒叙 asc:正序
select * from student order by clazzid asc
select * from student order by clazzid desc
## 多表联合查询 => 将两张表里面的数据综合起来查询

select * from clazz;
## select * from 表1,表2 where 表1.公共字段 = 表2.公共字段 and 字段 = ?
select * from student,clazz where student.clazzid = clazz.cid and student.susername = '张三'