Question

我已经习惯了mysql，你可以毫无问题地做到这一点。我想在SQL Server中运行以下语句，但它没有看到列C_COUNT。

SELECT 
   A.customers AS CUSTOMERS, 
  (SELECT COUNT(ID) FROM Partners_customers B WHERE A.ID = B.PIID) AS C_COUNT 
FROM Partners A
WHERE CUSTOMERS <> [C_COUNT]

是否可以在SELECT区域中使用任何数学运算，如

SELECT (CUSTOMERS - C_COUNT) AS DIFFERENCE

Answer 1

SQL Server不允许您在WHERE子句中使用别名。你必须有这样的东西：

SELECT *, Customers - C_COUNT "Difference"
FROM  (
    SELECT 
    A.customers AS CUSTOMERS, 
    (SELECT COUNT(ID) 
    FROM Partners_customers B WHERE A.ID = B.PIID) 
    AS C_COUNT FROM Partners A
) t
WHERE CUSTOMERS <> [C_COUNT]

或者，更好的是，消除内联计数：

select A.customers, count(b.id)
FROM Partners A
LEFT JOIN Partners_customers B ON A.ID = B.PIID
Group By A.ID
having a.customers <> count(b.id)

Answer 2

WITH A AS
(
    SELECT 
       A.customers AS CUSTOMERS, 
      (SELECT COUNT(ID) FROM Partners_customers B WHERE A.ID = B.PIID) AS C_COUNT 
    FROM Partners A
    WHERE CUSTOMERS <> [C_COUNT]
)
SELECT 
    *, 
    (CUSTOMERS - C_COUNT) AS DIFFERENCE 
FROM A

Answer 3

完全未经测试....

(select * from TabA 
 minus
 select * from TabB) -- Rows in TabA not in TabB
union all
( 
 select * from TabB 
 minus
 select * from TabA
) -- rows in TabB not in TabA

如何比较SQL Server中的两行

3 个答案: