是否可以联合两个具有相同结构的CTE的结果集

Question

我想联合以下CTE的结果集，以便获得4行数据。

Id Name 
------------- 
1 Test1 
2 Test2 
3 Test3 
4 Test4 

在SQL我想用如下

;with CTE1 (Id,Name) 
as 
( 
    select 1 as Id, 'Test1' as Name 
    union all 
    select 2, 'Test2' 
) 
select * from CTE1 
union all 
;with CTE2 (Id,Name) 
as 
( 
    select 3 as Id, 'Test3' as Name 
    union all 
    select 4, 'Test4' 
) 
select * from CTE2 

但是，我得到一个语法错误提示我不能使用UNION ALL两个热膨胀系数之间。 我该如何解决这个问题？

Answer 1

with CTE1 (Id,Name) 
as 
( 
    select 1 as Id, 'Test1' as Name 
    union all 
    select 2, 'Test2' 
), 
CTE2 (Id,Name) 
as 
( 
    select * from CTE1 
    union all 
    select 3 as Id, 'Test3' as Name 
    union all 
    select 4, 'Test4' 
) 
select * from CTE2 

或

with CTE1 (Id,Name) 
as 
( 
    select 1 as Id, 'Test1' as Name 
    union all 
    select 2, 'Test2' 
), 
CTE2 (Id,Name) 
as 
( 
    select 3 as Id, 'Test3' as Name 
    union all 
    select 4, 'Test4' 
) 
select * from CTE1 
union all 
select * from CTE2 

Answer 2

是的，但不是你正在做的方式。试试吧：

;with CTE1 (Id,Name) 
as 
( 
    select 1 as Id, 'Test1' as Name 
    union all 
    select 2, 'Test2' 
) 
,CTE2 (Id,Name) 
as 
( 
    select 3 as Id, 'Test3' as Name 
    union all 
    select 4, 'Test4' 
) 
select * from CTE1 
union all 
select * from CTE2 

你可以有多个CTE链接在一起。只有一个“WITH”和CTE之间的逗号。然后在CTE后面的声明中，您可以参考任何CTE。

Answer 3

;with CTE1 (Id,Name) 
as 
( 
    select 1 as Id, 'Test1' as Name 
    union all 
    select 2, 'Test2' 
) 
,CTE2 (Id,Name) 
as 
( 
    select 3 as Id, 'Test3' as Name 
    union all 
    select 4, 'Test4' 
) 
select * from CTE1 
union all 
select * from CTE2