Question

我正在尝试对具有以下更新触发器的表执行更新，但是我收到以下错误：

子查询返回的值超过1。这是不允许的子查询跟随=，！=，＆lt;，＆lt; =，＆gt;，＆gt; =或当子查询用作表达。

这是触发器......

如果photoRatingID的值设置为NULL，则会删除另一个表中的记录

IF UPDATE(photoRatingID)
BEGIN
    IF (SELECT photoRatingID FROM inserted) IS NULL
        BEGIN
            DELETE mbr_Media_Approval_Primary 
            FROM deleted, mbr_Media_Approval_Primary
            WHERE deleted.mbrID = mbr_Media_Approval_Primary.mbrID
        END
END

所有表格都包含唯一ID＆＃39; mbrID＆＃39;

Answer 1

您的SELECT photoRatingID FROM inserted会返回多行，如错误消息所示。因此IS NULL比较不起作用。您可以将或多或少的命令式方法转换为基于集合的方法，如下所示：

IF UPDATE(photoRatingID)
BEGIN
   DELETE map
   FROM mbr_Media_Approval_Primary map
       JOIN deleted d ON d.mbrID=map.mbrID
       JOIN inserted i ON i.mbrID=d.mbrID
   WHERE i.photoRatingID IS NULL
END

Answer 2

对于这种逻辑，您可以使用下面的CURSOR示例：

IF UPDATE(photoRatingID)
BEGIN
    DECLARE @photoRatingID AS int;  
    DECLARE KURSOR_photoRating CURSOR FOR
        SELECT photoRatingID FROM inserted; 
    OPEN KURSOR_photoRating;    
    FETCH NEXT FROM KURSOR_photoRating INTO @photoRatingID  
    WHILE @@FETCH_STATUS = 0
    BEGIN       
        IF (@photoRatingID IS NULL)
        BEGIN            
            DELETE mbr_Media_Approval_Primary 
            FROM deleted, mbr_Media_Approval_Primary
            WHERE deleted.mbrID = mbr_Media_Approval_Primary.mbrID          
        END
        FETCH NEXT FROM KURSOR_photoRating INTO @photoRatingID
    END 
    CLOSE KURSOR_photoRating;    
    DEALLOCATE KURSOR_photoRating;
END

更新触发器错误

2 个答案: