SQL 多并发 多人取号，防止重复取号SQL 办法

BEGIN TRAN
        SELECT  *  from 表明 WITH(HOLDLOCK)
        UPDATE 表名 SET 值=1 WHERE 字段=@carrierNo;
    
    COMMIT TRAN;

 

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ALTER PROCEDURE 名称     @字段名称 int AS BEGIN     DECLARE @num VARCHAR(80),@returnNumber VARCHAR(80);       BEGIN TRAN         SELECT @num=number FROM 表名 WITH(ROWLOCK,UPDLOCK) WHERE 字段=@ClearanceId AND ISNULL(状态,0)=0;         UPDATE  表名  WITH(ROWLOCK,UPDLOCK)                  SET 状态=1             WHERE 字段=@字段名称  AND ISNULL(状态,0)=0;         IF @@ROWCOUNT>0 BEGIN             SET @returnNumber=@num         END         ELSE BEGIN             SET @returnNumber='';         END;         SELECT @returnNumber;     COMMIT TRAN; END