Writing Basic SQL Select Statements（二）

已经很久没写SQL了，该忘记的都忘记了，如今回顾总结一下：

1.like----模糊查询
select * from [tablename] where [columnname] like '%"+char+"%'

2.distinct----压缩重复值
select distinct [columnname] from [tablename];

3.Between...and...-----取两者之间的值
select * from [tablename] where [columnname] between 40 and 50;

4.In(set)----离散的取值
select * from [tablename] where [columnname] in('1','2');

5.Order by ----排序
select * from [tablename] where [Condition] order by [columnname];

6.Group by ----分组
select [columnname1],sum([columnname2]) from [tablename] where [Condition] group by [columnname1]；

7.Having----对函数产生的值设定条件
select [columnname1],sum([columnname2]) from [tablename] where [Condition] group by [columnname1] Having sum([columnname2])>100；