sql - 无法查询查询？

Question

基本上我做了查询，但它没有工作'Msg 156，Level 15，State 1，Line 2 关键字'FROM'附近的语法不正确'

SELECT COUNT(*)
FROM
(
SELECT Group_ID, count(ID)
FROM dbo.S1_Users
WHERE Service_Plan = 'Multi User Foreign (B)'
GROUP BY Group_ID
HAVING count(ID) = 1
)

我知道它很容易修复，我搜索了谷歌但没有找到合适的

任何机构都可以对此进行解释吗？

Answer 1

您需要命名虚拟表并count(ID)从内部查询中命名列

SELECT COUNT(*)
FROM
(
SELECT Group_ID, count(ID) as ID_Count
FROM dbo.S1_Users
WHERE Service_Plan = 'Multi User Foreign (B)'
GROUP BY Group_ID
HAVING count(ID) = 1
) as A

您也可以完全删除计数感觉您没有使用它

SELECT COUNT(*)
FROM
(
SELECT Group_ID
FROM dbo.S1_Users
WHERE Service_Plan = 'Multi User Foreign (B)'
GROUP BY Group_ID
HAVING count(ID) = 1
) as A

Answer 2

试试这样：

SELECT COUNT(*)
FROM
(
    SELECT Group_ID, count(ID) As cnt
    FROM dbo.S1_Users
    WHERE Service_Plan = 'Multi User Foreign (B)'
    GROUP BY Group_ID
    HAVING count(ID) = 1
) A