mysql 查询求助

soccer

mysql> select * from bella;
+----+-----------+------------+
| id | bellatext | belladate  |
+----+-----------+------------+
|  1 | coherence | 2005-01-25 |
|  2 | jenny     | 2004-12-10 |
|  7 | eva       | 2004-01-01 |
|  8 | jones     | 2003-11-28 |
|  9 | LYN       | 2004-12-31 |
| 10 | leo       | 2004-11-11 |
| 11 | j%nny     | 2005-11-28 |
| 12 | beck      | 2005-01-11 |
| 15 | zero      | 2002-01-14 |
| 16 | pippo     | 2003-02-14 |
| 17 | jones     | 2004-07-07 |
+----+-----------+------------+
11 rows in set (0.00 sec)

mysql> select * from ty;
+-----------+---------------------+-------------+----------+
| bellatext | date                | no          | position |
+-----------+---------------------+-------------+----------+
| coherence | 2005-01-11 14:26:38 | 13917331887 | JS       |
| pretty    | 2004-12-31 00:00:00 | 13916351673 |          |
| elaine    | 2005-01-28 11:28:10 | 13901953895 | SH       |
| jones     | 2005-01-08 00:00:00 | 13916351673 |          |
| coco      | 2005-01-12 15:26:11 | 13341681012 | SH       |
| jack      | 2005-01-10 00:00:00 | 13916351673 |          |
+-----------+---------------------+-------------+----------+
6 rows in set (0.00 sec)

mysql> select ty.bellatext from ty ,bella where ty.bellatext=bella.bellatext ;
+-----------+
| bellatext |
+-----------+
|coherence|
| jones     |
| jones     |
+-----------+
3 rows in set (0.00 sec)


为什么会显示2个'jones' ?

soccer

mysql> select bellatext from ty where bellatext in(select bellatext from bella);
+-----------+
| bellatext |
+-----------+
| coherence |
| jones     |
+-----------+


要实现上述查询结果，用left join语句怎么写？

谢谢

soccer

select bellatext from ty where bellatext in(select bellatext from bella);

用left join命令能实现上面命令的查询结果吗？

懒猫

第一个问题，因为bella表有两个jones记录，如果只要一个，好想是select distinct （MS SQL Server上是这样，不知道mysql是不是）

没用过left join，帮不上忙