Question

我有3张桌子：

MariaDB [test]> DESCRIBE t1;
+-------+-----------+------+-----+---------+----------------+
| Field | Type      | Null | Key | Default | Extra          |
+-------+-----------+------+-----+---------+----------------+
| id    | int(11)   | NO   | PRI | NULL    | auto_increment |
| name  | char(150) | NO   |     | NULL    |                |
| time  | datetime  | NO   |     | NULL    |                |
+-------+-----------+------+-----+---------+----------------+


MariaDB [test]> DESCRIBE t2;
+-------+-----------+------+-----+---------+----------------+
| Field | Type      | Null | Key | Default | Extra          |
+-------+-----------+------+-----+---------+----------------+
| id    | int(11)   | NO   | PRI | NULL    | auto_increment |
| name  | char(150) | NO   |     | NULL    |                |
| time  | datetime  | NO   |     | NULL    |                |
+-------+-----------+------+-----+---------+----------------+


MariaDB [test]> DESCRIBE t3;
+-------+-----------+------+-----+---------+----------------+
| Field | Type      | Null | Key | Default | Extra          |
+-------+-----------+------+-----+---------+----------------+
| id    | int(11)   | NO   | PRI | NULL    | auto_increment |
| name  | char(150) | NO   |     | NULL    |                |
| time  | datetime  | NO   |     | NULL    |                |
+-------+-----------+------+-----+---------+----------------+

我想加入3个表并使用time字段对所有行进行排序。

我怎么能这样做？

Answer 1

您可以使用：

SELECT id, name, `time` FROM t1
UNION ALL 
SELECT id, name, `time` FROM t2
UNION ALL 
SELECT id, name, `time` FROM t3
ORDER BY `time`

您有多个具有相同架构的表的模式可能表示设计不佳。

Answer 2

您不希望加入您想要的联盟：

SELECT *
FROM
 (
   SELECT id, name, time FROM t1
   UNION ALL 
   SELECT id, name, time FROM t2
   UNION ALL 
   SELECT id, name, time FROM t3
 ) as dt
ORDER BY time

SQL - 如何按公共列对多个表进行排序

2 个答案: