如何在一个 SQL Server 查询中组合不同的计数

Question

我想在一个查询中组合不同的 Count 语句，以便最终查询只为每个 Count 返回一个数字（总数）。

以下查询单独工作，但我无法找到一种方法来组合它们而不重复相同的结果（嵌套表）并且不会丢失每个查询的单独名称（Union All）。

我的 SQL（只是为了方便查看在这里）：

(
    SELECT      COUNT(*) OVER() AS countB
    FROM        MOC_Log2 B
    WHERE       B.modBy = @modBy
    AND         B.lastUpdate = 'Added'
    FOR XML PATH(''), ELEMENTS, TYPE
),
(
    SELECT      COALESCE(SUM(D.vote), '0') AS countC
    FROM        MOC_Log3 C
    LEFT JOIN   MOC_Log3_Votes D
    ON          D.itemID = C.itemID
    WHERE       C.modBy = @modBy
    AND         C.lastUpdate = 'Added'
    FOR XML PATH(''), ELEMENTS, TYPE
),
(
    SELECT      COALESCE(SUM(F.vote), '0') AS countE
    FROM        MOC_Log4 E
    LEFT JOIN   MOC_Log4_Votes F
    ON          F.itemID = E.itemID
    WHERE       E.modBy = @modBy
    AND         E.lastUpdate = 'Added'
    FOR XML PATH(''), ELEMENTS, TYPE
)

Answer 1

只添加空列？

SELECT      COUNT(*) OVER() AS countB,
            Null AS  countC,
            Null AS countE
FROM        MOC_Log2 B
WHERE       B.modBy = @modBy
AND         B.lastUpdate = 'Added'
FOR XML PATH(''), ELEMENTS, TYPE
Union
SELECT      null,
            COALESCE(SUM(D.vote), '0'),
            null
FROM        MOC_Log3 C
LEFT JOIN   MOC_Log3_Votes D
ON          D.itemID = C.itemID
WHERE       C.modBy = @modBy
AND         C.lastUpdate = 'Added'
FOR XML PATH(''), ELEMENTS, TYPE
Union
SELECT      null,
            null,
            COALESCE(SUM(F.vote), '0')
FROM        MOC_Log4 E
LEFT JOIN   MOC_Log4_Votes F
ON          F.itemID = E.itemID
WHERE       E.modBy = @modBy
AND         E.lastUpdate = 'Added'
FOR XML PATH(''), ELEMENTS, TYPE

另请注意，我使用 Union 而非 Union all。很难判断这是否对您有用，因为我无法判断额外的空列是否会导致一些错误。