mysql - 将两个选择结果合并到一列中

Question

假设这是第一个 select 语句的结果

topic
 a 
 b
 c

这是第二个 select 语句的结果

user
 d
 e

如何将这两列合并为一个具有新列名称的列？我正在尝试使用 UNION 但它不起作用

SELECT topic FROM topic_table WHERE topic LIKE '%' 
UNION
SELECT user FROM user_table WHERE topic LIKE '%'

我想要的列就像

desired_column
    a
    b
    c
    d
    e

Answer 1

对主题列进行同等命名:

SELECT topic as topic FROM a WHERE topic LIKE '%' 
UNION ALL
SELECT other_topic as topic FROM b WHERE other_topic LIKE '%';

Playground : http://sqlfiddle.com/#!9/66ea3e/1