Question

我想结合以下CTE的结果集，以便获得4行数据。

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

我想使用的Sql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，我收到语法错误，提示我不能在两个CTE之间使用Union All。我怎么能绕过这个？

Answer 1

是的，但不是你这样做的方式。试试这种方式：

;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

您可以将多个CTE链接在一起。 CTE之间只有一个“WITH”和一个逗号。然后在CTE之后的陈述中，您可以引用任何这些CTE。

Answer 2

;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 3

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

是否可以将具有相同结构的两个CTE的结果集联合起来

3 个答案: