基本SQL语句总结
| 基本操作 |
基本语句 |
| 查询user表所有数据 |
select * from user |
| 查询user表中name字段所有数据 |
select name from user |
| 查询user表中符合条件的所有name字段 |
select name from user where password in (A,B,C) |
| 增加一条数据 |
insert into user (id,name,passowrd) values (1,Harrych,1994) |
| 删除一条数据 |
delete from user where id=1 |
| 修改一条数据 |
update user set name=Harry where id=1 |
| 分页查询 |
select * from user limit #{page},#{offset} |
| 分页排序查询 |
select * from user where 1=1 order by time desc limit #{page},#{offset} |
| 查询最前面2行数据 |
select top 2 * from user |
| like查询 (%代表缺少的字符） |
select * from user where name like 'h%' |
| "_"通配符查询（_代表缺少的一个字母） |
select * from user where name like '_on' |
| 查询name以H,C开头的数据 |
select * from user where name like '[HC]%' |
| 查询name不以H,C开头的数据 |
select * from user where name like '[!HC]%' |
| 查询指定范围的数据（左包右不包） |
select * from user where name between 'A' and 'B' |
| 查询指定范围外的数据 |
select * from user where name not between 'A' and 'B' |
| 指定别名查询 |
select * from user u where u.name='chen' and u.name='cao' and u.name='shi' |
| 多表联查（user表，person表） |
select user.name,person.name from person,user where person.id=user.id |
| join 内连接多表联查 |
select user.name,person.name from user inner join orders on user.id=person.id order by user.name |
| join 左连接多表查询 |
select user.name,person.name where user left join person on user.id=person.id order by user.name |
| join 右连接多表查询 |
select user.name,person.name where user right join person on user.id=person.id order by user.name |
| join 全连接多表查询 |
select user.name,person.name where user full join person on user.id=person.id |
| 多表合并查询（返回所有数据，包括重复的） |
select name from user union all select name from person |
| 多表合并查询（返回不重复的数据） |
select name from user union select name from person |
| 从一个表将指定数据插入到另一个表 |
select * into new_user from user |
| 将另一个数据库的user表数据插入到user表中 |
select * into user in 'aa.mdb' from user |
| 查询表中某个字段最大值,取名为max_id |
select max(id) max_id from user |
| 查询表中某个字段最小值 |
select min(id) from user |
| 查询表中最后一行某个字段的值 |
select last(name) from user |
| 查询表中第一行某个字段的值 |
select first(name) from user |
| 查询表中某个字段的列总和 |
select sum(id) from user |
| 查询所有不同name的在表中某个字段的总数量 |
select name,sum(id) from user group by name |
| 查询所有不同name的在表中某个字段的总数量 |
select name,sum(id) from user group by name having sum(id)<200 |
| 将name字段的值改成大写 |
select ucase(name) as name,password from user |
| 将name字段的值改成小写 |
select lcase(name) as name,password from user |
| 从name字段中提取前三个字符 |
select mid(name,1,3) as name from user |
| 获取name字段长度 |
select len(name) from user |
| 将A表中price舍去小数位 |
select round(price,0) as price from A |
| 获取当前数据库时间 |
select now() from user |
| 格式化查询的数据 |
select name ,price, format(now(),'YYYY-MM-DD') as now_time from A |