mysql - 在 2 个表中选择匹配的字符串

Question

表A

Id  | M  | D  |   Y   |
=======================
1  | 10  | 28  | 2012 |
2  | 11  | 29  | 2012 |
3  | 12  | 30  | 2012 |

表B

Id  | M  | D  |   Y   |
=======================
4  | 09  | 28  | 2012 |
5  | 11  | 29  | 2012 |
6  | 01  | 30  | 2013 |

我将按M和D搜索

例如：如果匹配 M = 11 AND D = 29 ... 那么将返回 ID(s) 2 , 5

我只能通过这样的一张桌子找到

mysql_query("SELECT * FROM TableA WHERE M='11' AND Y='29' ORDER BY D ASC , Id DESC;";)

但是如何在多个表中查找？

Answer 1

使用UNION两个SELECTs之间的子句

(SELECT Id, M, D, Y FROM TableA WHERE M='11' AND Y='29')
UNION
(SELECT Id, M, D, Y FROM TableB WHERE M='11' AND Y='29')
ORDER BY D ASC , Id DESC

Answer 2

SELECT * FROM TableA WHERE M='11' AND Y='29'
UNION
SELECT * FROM TableB WHERE M='11' AND Y='29'
ORDER BY D ASC , Id DESC;

Answer 3

您最好使用UNION ALL（如果tableB有相同的记录）来获取所有记录。否则只会UNION做。

SELECT * FROM TableA WHERE M='11' AND Y='29'
UNION ALL
SELECT * FROM TableB WHERE M='11' AND Y='29'
ORDER BY D ASC , Id DESC;