Question

为什么SQL Server不支持插入/更新？它只支持选择。 SQL Server中有In Duplicate Key MySQL的替代方法吗？

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IF(SELECT accountNo 
   FROM MeterReading 
   WHERE accountNo = 1111) is NULL 
    (INSERT INTO dbo.MeterReading  
     VALUES (1, 1, 1, 1)); 
ELSE 
    (UPDATE dbo.MeterReading 
     SET currentReading = 1223 
     WHERE accountNo = 1111);

Answer 1

你可以选择UPSERT：

UPDATE MeterReading SET currentReading=1223 WHERE accountNo=1111

IF @@ROWCOUNT = 0
   INSERT INTO MeterReading VALUES (1, 1, 1, 1)

Answer 2

试试这个语法：

IF NOT EXISTS(SELECT accountNo 
               FROM MeterReading 
               WHERE accountNo = 1111) 
  BEGIN 
    INSERT INTO dbo.MeterReading  
    VALUES (1, 1, 1, 1) 
  END 
ELSE 
  BEGIN 
  UPDATE dbo.MeterReading 
  SET currentReading = 1223 
  WHERE accountNo = 1111
  END

Answer 3

您也可以尝试合并

MERGE MeterReading AS target  
    USING (SELECT 1111, 1223) AS source (accountNo, currentReading)  
    ON (target.accountNo = source.accountNo )  
WHEN MATCHED THEN   
    UPDATE SET currentReading  = source.currentReading   
WHEN NOT MATCHED THEN  
    INSERT (col1,col2,col3,col4)  
    VALUES (1, 1, 1, 1);

SQL Server如果有，则插入/更新

3 个答案: