我不确定我需要什么类型的连接,因为我不熟悉尝试以这种方式覆盖数据或者如果它是可行的。SQL自然连接POSTGRES
我有两个表这两者有着相似的一组数据,并且两者都涉及到3号的父表通Room_id.
我有一个表称为Room_rates存储的平均价格为每间客房(ROOM_ID)
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
| id | room_id | dayofweek | price | source | created_at | updated_at |
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
| 87936 | 2517 | 0 | 14.58 | 1 | 2010-02-22 17:47:14 +0100 | 2010-02-22 17:47:14 +0100 |
| 87937 | 2517 | 1 | 14.58 | 1 | 2010-02-22 17:47:14 +0100 | 2010-02-22 17:47:14 +0100 |
| 87938 | 2517 | 2 | 14.52 | 1 | 2010-02-22 17:47:14 +0100 | 2010-02-22 17:47:14 +0100 |
| 87939 | 2517 | 3 | 14.52 | 1 | 2010-02-22 17:47:14 +0100 | 2010-02-22 17:47:14 +0100 |
| 87940 | 2517 | 4 | 14.52 | 1 | 2010-02-22 17:47:15 +0100 | 2010-02-22 17:47:15 +0100 |
| 87941 | 2517 | 5 | 14.4 | 1 | 2010-02-22 17:47:15 +0100 | 2010-02-22 17:47:15 +0100 |
| 87942 | 2517 | 6 | 14.63 | 1 | 2010-02-22 17:47:15 +0100 | 2010-02-22 17:47:15 +0100 |
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
和称为可获取表,有具体日期
+--------+-------+-------+------------+---------+---------------------------+---------------------------+--------+
| id | price | spots | bookdate | room_id | created_at | updated_at | source |
+--------+-------+-------+------------+---------+---------------------------+---------------------------+--------+
| 221389 | 14.3 | 1 | 2010-03-01 | 2517 | 2010-02-21 22:31:06 +0100 | 2010-02-21 22:31:06 +0100 | 1 |
| 221390 | 14.3 | 1 | 2010-03-02 | 2517 | 2010-02-21 22:31:06 +0100 | 2010-02-21 22:31:06 +0100 | 1 |
| 221391 | 14.3 | 1 | 2010-03-03 | 2517 | 2010-02-21 22:31:06 +0100 | 2010-02-21 22:31:06 +0100 | 1 |
| 221392 | 14.3 | 1 | 2010-03-04 | 2517 | 2010-02-21 22:31:06 +0100 | 2010-02-22 17:47:19 +0100 | 1 |
| 221393 | | 0 | 2010-03-05 | 2517 | 2010-02-21 22:31:06 +0100 | 2010-02-22 17:47:19 +0100 | 1 |
| 221394 | | 0 | 2010-03-06 | 2517 | 2010-02-21 22:31:06 +0100 | 2010-02-22 17:47:19 +0100 | 1 |
| 228185 | | 0 | 2010-03-07 | 2517 | 2010-02-22 17:47:19 +0100 | 2010-02-22 17:47:19 +0100 | 1 |
| 228186 | 14.3 | 1 | 2010-03-08 | 2517 | 2010-02-22 17:47:19 +0100 | 2010-02-22 17:47:19 +0100 | 1 |
| 228187 | 14.3 | 1 | 2010-03-09 | 2517 | 2010-02-22 17:47:19 +0100 | 2010-02-22 17:47:19 +0100 | 1 |
| 228188 | 14.3 | 1 | 2010-03-10 | 2517 | 2010-02-22 17:47:19 +0100 | 2010-02-22 17:47:19 +0100 | 1 |
+--------+-------+-------+------------+---------+---------------------------+---------------------------+--------+
率目前我使用两个单独的海rch结果,当前为Availables
特定日期范围内的数据存在,或者不存在。如果没有,我只使用Room_rate
平均值进行备份查询。
我想使用可用的地方它有可用的价格,但不知何故加入Room_rates填补空白,如果价格不可用或可能根本没有记录。
我怎么能做到这一点?