查询:
一:查询所有数据
select * from Info 查所有数据
select Code,Name from Info 查特定列
二: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
三: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%'
四: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
五: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
六: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
七:分页查询
select * from Car limit 0,5 跳过几条数据取几条数据
八:去重查询
select distinct Brand from Car
作者:点碎的阳光
原文链接:https://www.cnblogs.com/tianming18/p/10271909.html
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