mysql - 对两个没有连接的表进行组合 SELECT 查询

Question

是否可以对两个完全没有连接的表运行组合 SELECT 查询？

**Table A**         **Table B***
id | A | B | C      id | D | E | F
---------------     ---------------
X1 | 1 | 2 | 3      Y1 | 1 | 2 | 3
---------------     ---------------
X2 | 1 | 2 | 3      Y2 | 1 | 2 | 3
---------------     ---------------
X3 | 1 | 2 | 3      Y3 | 1 | 2 | 3

在两个查询中它将是:

   SELECT A,B FROM Table A WHERE id=X2
   SELECT D,E FROM Table B WHERE id=Y1

如果可能的话，我想将这两者结合起来

SELECT (A,B FROM Table A WHERE id=X2) AND (D,E FROM Table B WHERE id=Y1)

只有一个结果集。

Answer 1

使用UNION

(SELECT A as col1 ,B as col2 FROM Table A WHERE id=X2) union (SELECT D as col1,E as col2 FROM Table B WHERE id=Y1)