意外「子查詢返回多個值」

Question

表有這樣的結構：grouptable將> lineGroupJoinTable> linesTable（名字被混淆的名字） 我有以下查詢返回此錯誤：

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

的事情是，我期望，因爲子查詢是組，我不應該得到這個錯誤。我可能錯過了一些東西。

UPDATE dbo.groupTable 
SET fieldToUpdate = CASE WHEN fieldToUpdate IS NULL THEN NULL ELSE 
(
    SELECT sumTable.fieldToSum FROM 
    dbo.groupTable gt 
    INNER JOIN 
    (
     SELECT lgjt.groupdId1, lgjt.groupdId2, SUM(lt.fieldToSum) as fieldToSum 
     FROM lineGroupJoinTable lgjt 
     INNER JOIN linesTable lt 
      ON 
       lt.fieldToSum IS NOT NULL AND lt.fieldToSum > 0 AND 
       lgjt.lineId1 = lt.lineId1 AND lgjt.lineId2 = lt.lineId2 
     GROUP BY lgjt.groupdId1, lgjt.groupdId2 

    ) sumTable 
    ON sumTable.groupdId1 = gt.groupdId1 AND sumTable.groupdId2 = gt.groupdId2 
) 
END 

這種變化還嘗試以下建議，但返回相同的錯誤：

UPDATE dbo.groupTable 
SET fieldToUpdate = CASE WHEN fieldToUpdate IS NULL THEN NULL ELSE 
(
    SELECT SUM(sumTable.fieldToSum) FROM 
    dbo.groupTable gt 
    INNER JOIN 
    (
     SELECT lgjt.groupdId1, lgjt.groupdId2, SUM(lt.fieldToSum) as fieldToSum 
     FROM lineGroupJoinTable lgjt 
     INNER JOIN linesTable lt 
      ON 
       lt.fieldToSum IS NOT NULL AND lt.fieldToSum > 0 AND 
       lgjt.lineId1 = lt.lineId1 AND lgjt.lineId2 = lt.lineId2 
     GROUP BY lgjt.groupdId1, lgjt.groupdId2 

    ) sumTable 
    ON sumTable.groupdId1 = gt.groupdId1 AND sumTable.groupdId2 = gt.groupdId2 
    GROUP BY gt.groupdId1, gt.groupdId2 
) 
END 

Answer 1

可能是因爲dbo.groupTable對組合ID1和ID2多重價值。我建議在id1和id2列上進行分組並做一個SUM，那樣的話你只有1個結果。

UPDATE dbo.groupTable 
SET fieldToUpdate = CASE WHEN fieldToUpdate IS NULL THEN NULL ELSE 
(
    SELECT SUM(sumTable.fieldToSum) FROM 
    dbo.groupTable gt 
    INNER JOIN 
    (
     SELECT lgjt.id1, lgjt.id2, SUM(lt.fieldToSum) as fieldToSum 
     FROM lineGroupJoinTable lgjt 
     INNER JOIN linesTable lt 
      ON 
       lt.fieldToSum IS NOT NULL AND lt.fieldToSum > 0 AND 
       lgjt.id3 = lt.id3 AND lgjt.id4 = lt.id4 
     GROUP BY lgjt.id1, lgjt.id2 
    ) sumTable 
    ON sumTable.id1 = gt.id1 AND sumTable.id2 = gt.id2 
    GROUP BY gt.id1, gt.id2 
) 
END