mysql分组查询前n条数据

查询该表中,每组的最大两个数:

select a.* from hard a where (select count(*) from hard where aa = a.aa and bb > a.bb ) < 2 order by a.aa,a.bb desc

此处 2 即为n

(查询单表不分组的前n条最大数据: select DISTINCT bb from hard order by bb desc limit 2)

结果图:

 原理剖析:

mysql分组查询前n条数据

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