我遇到了这个小问题，
当我运行这个查询时它工作正常，但是 DISTINCT 返回所有不应该的重复值，我只是想知道它为什么会这样。
询问
SELECT DISTINCT `dstuser` ,
DATE_FORMAT( `t` , '%M %e, %Y' ) AS `date`
FROM `mail`
表
+---------------------+---------+---------+---------+---------+--------+
| time | srcuser | srchost | dstuser | dsthost | size |
+---------------------+---------+---------+---------+---------+--------+
| 2006-05-12 15:02:49 | phil | mars | phil | saturn | 4522 |
| 2006-05-11 10:15:08 | barb | saturn | tricia | mars | 58274 |
| 2006-05-12 12:48:13 | tricia | mars | gene | venus | 194925 |
| 2006-05-12 15:02:49 | phil | mars | phil | saturn | 1048 |
| 2006-05-12 12:48:13 | tricia | mars | link | asure | 524111 |
+---------------------+---------+---------+---------+---------+--------+
退货
+---------+--------------+
| dstuser | date |
+---------+--------------+
| tricia | May 11, 2006 |
| gene | May 12, 2006 |
| phil | May 12, 2006 |
| tricia | May 13, 2006 |
| barb | May 14, 2006 |
| tricia | May 14, 2006 |
| phil | May 14, 2006 |
| gene | May 15, 2006 |
| phil | May 15, 2006 |
| tricia | May 15, 2006 |
| barb | May 16, 2006 |
| tricia | May 17, 2006 |
| gene | May 19, 2006 |
+---------+--------------+
13 rows in set (0.00 sec)