如何选择另一个表中存在多个列的ID？

Question

假设我有两个表TableA和TableB，其结构如下所示：-

**TableA**

id | col_1  | col_2

1  |   A    |   B
2  |   C    |   D
3  |   E    |   F
4  |   G    |   H


**TableB**

id | TableA_first_col_id | TableA_second_col_id
1  |  1                  |   2
2  |  1                  |   3

现在，我想检查TableB TableA_first_col_id列或TableA_second_col_id列中是否存在TableA id。 结果应该是

**TableA.id**
1
2
3

如何为此编写优化的mysql查询？

Answer 1

select *
from table1 t1
where not exists (
    select 1
    from table2 t2 
    where t1.id = t2.id and t1.program = t2.program
)

Answer 2

尝试以下；

Select A.id
From TableA A
Where A.id in (select TableA_first_col_id From TableB) OR
      A.id in (select TableA_second_col_id from TableB)

Answer 3

select id from tableA where exists 
(   select id
    from tableB
    where tableA.id = tableB.first_col_id or tableA.id = tableB.second_col_id
)