如何组合两个不同的CTE

Question

为简单起见，我有以下示例：

;WITH myCTE (CustID, Co) AS
(
SELECT CustomerID, CompanyName FROM Customers
)
SELECT CompanyName FROM Customers WHERE CustomerID = 'ALFKI'

union all --this does not work with two With statements

;WITH myCTE2 (CustID, Co) AS
(
SELECT CustomerID, CompanyName FROM Customers
)
SELECT CompanyName FROM Customers WHERE CustomerID = 'BBICT' 

Answer 1

;WITH myCTE (CustID, Co) AS
(
SELECT CustomerID, CompanyName FROM Customers
), myCTE2 (CustID, Co) AS
(
SELECT CustomerID, CompanyName FROM Customers
)
SELECT Co FROM myCTE WHERE CustID = 'BBICT' 
union all
SELECT Co FROM myCTE2 WHERE CustID = 'ALFKI'

编辑：

假设OP选择了一个糟糕的例子。

否则，所需要的只是

SELECT CompanyName FROM Customers WHERE CustomerID IN ('ALFKI', 'BBICT' )

Answer 2

您只需要将两个查询分开：

;WITH myCTE (CustID, Co) AS
(
SELECT CustomerID, CompanyName FROM Customers
)
,
myCTE2 (CustID, Co) AS
(
SELECT CustomerID, CompanyName FROM Customers
)
SELECT CompanyName FROM Customers WHERE CustomerID = 'BBICT'
UNION
SELECT CompanyName FROM Customers WHERE CustomerID = 'ALFKI'