select top 10 D,类别,书名,销售额 from table order by 销售额 desc
select * from yourtable as A where id in (select top 10 id from yourtable where 类别 = A.类别 order by 销售额 desc) order by 类别, 销售额
求分类的top问题select * from table as A where 销售额 in ( select top 10 销售额 from table where 类别=A.类别 order by 销售额)orselect * from table aa where exists(select 1 from (select top 10 销售额 from table where 类别=aa.类别) bb where bb.销售额=aa.销售额)
恭喜 zqllyh (学习Stupid As Pig中...) 兄升级
来晚了,哈哈。。恭喜找感觉!select * from 表 a where id in (select top 10 id from 表 where 类别=a.类别 order by 销售额 desc) order by 类别,销售额 desc
谢谢各位高手! 请问大家这句SQL有什么办法再优化以下,提高一下速度!
select * from 表 a where id in (select top 10 id from 表 where 类别=a.类别 order by 销售额 desc) order by 类别,销售额 desc语句就是这样了,对你的“类别”加索引
pengdali(大力)兄: 我的DB中有600万条测试数据,以后可能上亿, select * from 表 a where id in (select top 10 id from 表 where 类别=a.类别 order by 销售额 desc) order by 类别,销售额 desc 这样的嵌套系统好象吃不消,
(select top 10 id from yourtable where 类别 = A.类别 order by 销售额 desc)
order by 类别, 销售额
where 销售额 in ( select top 10 销售额 from table where 类别=A.类别 order by 销售额)orselect * from table aa where exists(select 1 from
(select top 10 销售额 from table where 类别=aa.类别) bb where bb.销售额=aa.销售额)
请问大家这句SQL有什么办法再优化以下,提高一下速度!
我的DB中有600万条测试数据,以后可能上亿,
select * from 表 a where id in (select top 10 id from 表 where 类别=a.类别 order by 销售额 desc) order by 类别,销售额 desc
这样的嵌套系统好象吃不消,