我现在碰到这样的一个情况:
我想从两个表里面关联查出数据sql语句是这样的:
select a.projshortname, a.projmanager, a.projver, b.optrid, b.checkdate from fitdoa.tb_oa_project a left join tb_oa_sys_check_log b ON a.projid = b.projid where a.projid='proj01' and checkdate='2010-01-07';
其中where的约束条件 projid 和checkdate 都是有很多个相同的数据;就像这样:
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
+---------------+-------------+------------+-----------+------------+
我想只查出其中的一条怎么办?sql语句应该怎么写?
我想从两个表里面关联查出数据sql语句是这样的:
select a.projshortname, a.projmanager, a.projver, b.optrid, b.checkdate from fitdoa.tb_oa_project a left join tb_oa_sys_check_log b ON a.projid = b.projid where a.projid='proj01' and checkdate='2010-01-07';
其中where的约束条件 projid 和checkdate 都是有很多个相同的数据;就像这样:
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
| 短信营销 | yaogl | release1.0 | GAOBQ | 2010-01-07 |
+---------------+-------------+------------+-----------+------------+
我想只查出其中的一条怎么办?sql语句应该怎么写?
from fitdoa.tb_oa_project a left join tb_oa_sys_check_log b ON a.projid = b.projid
where a.projid='proj01'
and checkdate='2010-01-07';
只是返回一条记录。不同的功能。