Question

我创建了这个MERGE语句，它从Temp获取数据并将其放入Word表中。这是Temp的模式：

CREATE TABLE [dbo].[Temp] (
    [Word] VARCHAR (MAX) NULL,
    [SFI]  REAL          NULL,
    [U]    INT           NULL,
    [D]    REAL          NULL
);

这是MERGE：

MERGE [dbo].[Word] as target
USING [dbo].[Temp] as source
ON target.[WordId] = source.[Word]
WHEN MATCHED THEN 
    UPDATE SET [NAWL963SFI] = source.[SFI], [NAWL963U] = source.[U], [NAWL963D] = source.[D]
WHEN NOT MATCHED THEN 
    INSERT ([WordId],[NAWL963SFI],[NAWL963U], [NAWL963D], [NAWL963]) 
    VALUES (source.[Word],source.[SFI],source.[U], source.[D], 1);

当它运行时，它给我一个错误说“

Msg 515, Level 16, State 2, Line 41
Cannot insert the value NULL into column 'WordId', table 'ab.dbo.Word'; column does not allow nulls. UPDATE fails.
The statement has been terminated.

我检查过Temp

中没有空值

 SELECT count(*) from Temp where Word = null;

有没有人对我如何调试这个有任何建议，或者我合并的方式有什么问题？

Answer 1

嗯，您没有正确搜索NULL，列永远不会等于NULL，您必须使用IS NULL和{{ 1}}检查列是否为空：

IS NOT NULL

尝试查找此行

 SELECT count(*) from Temp where Word is null;

对此：

USING [dbo].[Temp] as source

我尝试更新主表

1 个答案: