MYSQL 分组

标准的分组Mysql，取的分组全部数据: select * from table where id = id group by id order by id desc limit 1,1;

当使用分组取数量时，先取的全部分组，而后取数量： sleect count() from (select count() from table where id = id group by id order by id desc limit 1,1) as g;

当对分组组内内容排序时，先对数据排序，而后分组取的排序后的数据： select * from (select * from table order by id desc) as g where id = id group by id limit 1,1;

当对分组组内内容排序和分组排序使用，各自排序： select * from (select * from table order by id desc) as g where id = id group by id order by id desc limit 1,1;