mysql取内容时先order by后group by

在mysql里取数据时怎么先order by后group by？其实很简单，sql语句如下：

select count(count_filed) from (select * from table order by order_by_filed) table group by group_by_field;

这样就可以实现对group by里的内容排序，按你的意思先order by后group by!