这个还能优化吗？

[沈笑菲]

select top 5 Id,[Type] from A  where [Type] =0 
union all 
select top 5 Id,[Type] from A  where [Type] =1

需求是根据表中的类别（0-3），每个类别都取5条，上面这样的写法（只是模拟先取2个类别）还能优化不？

[xiaodongni]

用ROW_NUMBER ,你的代码少了排序列啊。不然TOP 5 就是随机取的了 select * from (select * ,row_number()over(partition by type order by colname) asn from A) as t where t.n<=5

[沈笑菲]

引用 1 楼 alimake 的回复:

用ROW_NUMBER ,你的代码少了排序列啊。不然TOP 5 就是随机取的了 select * from (select * ,row_number()over(partition by type order by colname) asn from A) as t where t.n<=5

真真真真是厉害