mysql之groupby再排序的问题:

mysql group by + order by 查询，获取money 最高的uid
  
//简单方法，但是不能准确获取当前那一行数据
SELECT id, uid,MAX(money) as cc, datatime FROM d_rewards GROUP BY uid ORDER BY cc DESC;
  
//下面这个子查询的结果有了，但是 对于 group by 却没有生效
SELECT
	r.id,
	r.uid,
	r.money,
	r.datatime 
FROM
	( SELECT id, uid, money, datatime FROM d_rewards ORDER BY money DESC) r 
GROUP BY
	r.uid 
ORDER BY
	r.money DESC;

  
//加上 limit 就可以了，原因待定...，但是 limit 的值是一个问题
SELECT
	r.id,
	r.uid,
	r.money,
	r.datatime 
FROM
	( SELECT id, uid, money, datatime FROM d_rewards ORDER BY money DESC limit 8) r 
GROUP BY
	r.uid 
ORDER BY
	r.money DESC;