非常非常难的查询

Question

我有一个表，如下所示：

**A----B----C----D----F----E** 

1----2----3-----4----5----6 

1----2----3-----4----5----6 

1----2----3-----4----5----6 

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现在我想打一个查询，如下表，表导致的字段值C，下面列A，B的d ，列F中的值，E以下的列A，B，

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最终表

**A----B** 

1----2 

1----2 

1----2 

3----4 

3----4 

3----4 

5----6 

5----6 

5----6 

Answer 1

试试这个：

SELECT a AS A, b AS B 
FROM tablea 
UNION ALL 
SELECT c AS A, d AS B 
FROM tablea 
UNION ALL 
SELECT f AS A, e AS B 
FROM tablea; 

Answer 2

你想要一个基本union all查询：

select a, b from table t union all 
select c, d from table t union all 
select f, e from table t;