1 | 查询所有数据 

 

select * from Info 查所有数据

 

select Code,Name from Info 查特定列

 

 

 2 | 根据条件查 

 

select * from Info where Code='p001' 一个条件查询

 

select * from Info where Code='p001' and Nation='n001' 多条件 并关系 查询

 

select * from Info where Name='胡军' or Nation='n001' 多条件 或关系 查询

 

select * from Car where Price>=50 and Price<=60 范围查询

 

select * from Car where Price between 50 and 60 范围查询

 

 

 

3 | 模糊查询 

 

select * from Car where Name like '%型' %通配符代表任意多个字符

 

select * from Car where Name like '%奥迪%' _通配符代表任意一个字符

 

select * from Car where Name like '_马%'

 

 

 4| 排序 

 

select * from Car order by Price asc 按照价格升序排列

 

select * from Car order by Price desc 按照价格降序排列

 

select * from Car order by Price,Oil 按照两列进行排序，前面的为主要的

 

 

 5 | 统计函数（聚合函数）

 

select count(Code) from Car 查询表中有多少条数据

 

select max(Price) from Car 取价格的最大值

 

select min(Price) from Car 取价格的最小值

 

select sum(Price) from Car 取价格的总和

 

select avg(Price) from Car 取价格的平均值

 

 

 6 | 分组查询 

 

select Brand from Car group by Brand having count(*)>2 查询所有系列中数量大于2的

 

 

 7 | 分页查询 

 

select * from Car limit 0,5 跳过几条数据取几条数据

 

 

 8 | 去重查询 

 

select distinct Brand from Car