select * from (select * from t order by logtime desc) t2 group by username
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关于group by的排序问题
select * from t group by username order by logtime desc MySQL对上述语句的处理方式是: 先群组,群组后再排序 但是我现在想排序后再群组该如何解决呢? --------- ps.用如下方式可以解决, 但是感觉效率太低, 不知道还有没有更好的办法! 谢谢大家! select * from (select * from t order by logtime desc) t2 group by username
mysql> select max(id),user_id from d group by user_id order by max(id);
+---------+---------+
| max(id) | user_id |
+---------+---------+
| 2 | 8 |
| 4 | 7 |
| 5 | 9 |
+---------+---------+
3 rows in set (0.00 sec)