SQL子查询与否？

Question

我试图找到一个将从两个表中选择但不加入这两个表的查询,因为我不希望结果在一行上.

可以说我有这些表:

Persons1                 Persons2
Number Name    Surname   Number  Name   Surname
-----------------------  ------------------------- 
1      Peter   Miller    1       Frank  Farian 
2      Hans    Geige     2       Thomas Müller

当我使用此查询时:

SELECT
  NEW.NAME,
  OLD.NAME
FROM
  PERSONS1 NEW,
  PERSONS2 OLD
WHERE
  NEW.Number = 1 AND
  OLD.Number = 1

我得到以下结果:

Peter   Frank

如何编写查询以获取:

Peter
Frank

Answer 1

使用UNION:

SELECT NEW.NAME
FROM PERSONS1 NEW
WHERE NEW.Number = 1
UNION 
SELECT OLD.NAME
FROM PERSONS2 OLD
WHERE OLD.Number = 1