按组

Question

嗨，我的表格是这样的：

 current | similar
   8     |2
   8     |4
   8     |4
   8     |4
   8     |4
   8     |5
   8     |5

但我想以这种方式首先4，因为它重复4次，5秒cuz重复两次，最后2次：

 current | similar
   8     |4
   8     |4
   8     |4
   8     |4
   8     |5
   8     |5
   8     |2

我试过： select * from mytable order by similar，但我先得到5分4秒，最后2分

也：

select * from mytable order by count(similar) but only one row is returned

最后： select *, count(similar) as a from mytable order by a，但即使是小组也没有工作，我该如何实现呢？感谢

Answer 1

首先，您可以计算similar组中每个current字段的出现次数，然后使用原始表格join对其进行排序，以对结果集进行排序。

select t1.current, t1.similar
from tbl t1
join (
    select current, similar, count(*) as ttl
    from tbl
    group by current, similar
) t2 on t1.current = t2.current and t1.similar = t2.similar
order by t1.current, t2.ttl desc

SQLFiddle