如何在单个SELECT语句中具有多个公用表表达式？

我正在简化一个复杂的select语句，因此以为我会使用公用表表达式。

声明单个CTE可以正常工作。

WITH cte1 AS (
    SELECT * from cdr.Location
    )

select * from cte1 

是否可以在同一SELECT中声明和使用多个cte？

即此SQL给出了一个错误

WITH cte1 as (
    SELECT * from cdr.Location
)

WITH cte2 as (
    SELECT * from cdr.Location
)

select * from cte1    
union     
select * from cte2

错误是

Msg 156, Level 15, State 1, Line 7
Incorrect syntax near the keyword 'WITH'.
Msg 319, Level 15, State 1, Line 7
Incorrect syntax near the keyword 'with'. If this statement is a common table expression, an xmlnamespaces clause or a change tracking context clause, the previous statement must be terminated with a semicolon.

注意 我尝试放入分号并出现此错误

Msg 102, Level 15, State 1, Line 5
Incorrect syntax near ';'.
Msg 102, Level 15, State 1, Line 9
Incorrect syntax near ';'.

可能不相关，但这在SQL 2008上。

我认为应该是这样的：

WITH 
    cte1 as (SELECT * from cdr.Location),
    cte2 as (SELECT * from cdr.Location)
select * from cte1 union select * from cte2

基本上，WITH这里只是一个子句，与其他采用列表的子句一样，“，”是适当的定界符。

上面提到的答案是正确的：

WITH 
    cte1 as (SELECT * from cdr.Location),
    cte2 as (SELECT * from cdr.Location)
select * from cte1 union select * from cte2

另外，您还可以从cte2中的cte1查询：

WITH 
    cte1 as (SELECT * from cdr.Location),
    cte2 as (SELECT * from cte1 where val1 = val2)

select * from cte1 union select * from cte2

val1,val2 只是表达的假设。

希望该博客对您有所帮助：http : //iamfixed.blogspot.de/2017/11/common-table-expression-in-sql-with.html