Sql 每年新增一千万行，重复一千次day@student35k tps=“每秒35000个事务”。TRY CATCH通过捕获唯一约束冲突错误（错误号2627）并忽略它来防止插入重复条目。如果不是2627，则CATCH只会重新显示错误。此代码段存在问题，因为唯一索

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每年新增一千万行，重复一千次day@student35k tps=“每秒35000个事务”。TRY CATCH通过捕获唯一约束冲突错误（错误号2627）并忽略它来防止插入重复条目。如果不是2627，则CATCH只会重新显示错误。此代码段存在问题，因为唯一索引冲突为错误2601。所以你必须检查这两种代码。此解决方案也仅适用于单行插入。如果尝试从一个表插入到另一个表，则需要不同的策略。在这种情况下，可以删除“WHEN MATCHED THEN”，因为Adam只需要在缺少时插入，而不需要向上插入。很抱歉，但不需要在merge语句中添加保持锁定提示，您将遇到OP所关心的确切问题。有关@EBarr的更多信息，请参阅point@MartinSmith-这正是我遇到这个问题时读到的文章！感谢您的参考。MSDN文档（在性能提示中）指出，除非需要复杂性，否则您应该在不存在的位置使用插入而不是合并。。。这正是我在上一个答案中被忽略的一点+向你们两个致敬！

INSERT INTO TheTable
SELECT
    @primaryKey,
    @value1,
    @value2
WHERE
    NOT EXISTS
    (SELECT
        NULL
    FROM
        TheTable
    WHERE
        PrimaryKey = @primaryKey)

INSERT INTO TheTable
WITH
    (HOLDLOCK,
    UPDLOCK,
    ROWLOCK)
SELECT
    @primaryKey,
    @value1,
    @value2
WHERE
    NOT EXISTS
    (SELECT
        NULL
    FROM
        TheTable
    WITH
        (HOLDLOCK,
        UPDLOCK,
        ROWLOCK)
    WHERE
        PrimaryKey = @primaryKey)

INSERT INTO TheTable 
SELECT 
    @primaryKey, 
    @value1, 
    @value2 
WHERE 
    NOT EXISTS 
    (SELECT 0
     FROM TheTable WITH (UPDLOCK, HOLDLOCK)
     WHERE PrimaryKey = @primaryKey) 

     DECLARE @existing varchar(10)
    SET @existing = (SELECT primaryKey FROM TABLE WHERE param1field = @param1 AND param2field = @param2)

    IF @existing is not null
    BEGIN
    INSERT INTO Table(param1Field, param2Field) VALUES(param1, param2)
    END
    ELSE
    Return 0
END

BEGIN TRY
   INSERT etc
END TRY
BEGIN CATCH
    IF ERROR_NUMBER() <> 2627
      RAISERROR etc
END CATCH

MERGE INTO Target
USING (VALUES (@primaryKey, @value1, @value2)) Source (key, value1, value2)
ON Target.key = Source.key
WHEN MATCHED THEN
    UPDATE SET value1 = Source.value1, value2 = Source.value2
WHEN NOT MATCHED BY TARGET THEN
    INSERT (Name, ReasonType) VALUES (@primaryKey, @value1, @value2)

    BEGIN TRY
       INSERT etc
    END TRY
    BEGIN CATCH
        IF ERROR_NUMBER() <> 2627
          BEGIN
                DECLARE @ErrorMessage NVARCHAR(4000);
                DECLARE @ErrorSeverity INT;
                DECLARE @ErrorState INT;

                SELECT @ErrorMessage = ERROR_MESSAGE(),
                @ErrorSeverity = ERROR_SEVERITY(),
                @ErrorState = ERROR_STATE();

                    RAISERROR (
                        @ErrorMessage,
                        @ErrorSeverity,
                        @ErrorState
                    );
          END
    END CATCH