两表的数据，合成一表

Question

表A
+--------------+
|    ID        |
+--------------+
|            1 | 
|            2 | 
|            3 | 
|            4 | 
|            5 | 
+--------------+
表B
+--------------+
|    ID        |
+--------------+
|           13 | 
|           14 | 
|           15 | 
+--------------+期待查询的结果为
+--------------+
|    ID        |
+--------------+
|            1 | 
|            2 | 
|            3 | 
|            4 | 
|            5 | 
|           13 | 
|           14 | 
|           15 | 
+--------------+

Answer 1

select * from a
union all
select * from b

Answer 2

select id from 表a union all select id from 表b

Answer 3

SELECT * FROM A
UNION ALL
SELECT * FROM B

Answer 4

SELECT * FROM A
UNION ALL
SELECT * FROM B

Answer 5

根据是否有重复的数据，用union或者union all