Question

当Dense_Rank（）值增加时，我想重新启动SELECT语句中Row_Number（）列的编号。我尝试用光标做到这一点，但我面临着舍入我的数据的问题。有没有其他方法可以不使用游标？

DECLARE @RowNum as INT;
DECLARE @DenseRank as INT;
DECLARE @DenseRankPrevious as INT;
DECLARE @RD_ROI1_minus_RD_ROI3 as NVARCHAR(MAX);
DECLARE @RD_ROI2_minus_RD_ROI3 as NVARCHAR(MAX);
DECLARE @Cursor as CURSOR;

SET @RowNum = 0;
SET @Cursor = CURSOR FOR
    SELECT DENSE_RANK() OVER (ORDER BY [RD_RF_ID]) AS DenseRank, [RD_ROI1_minus_RD_ROI3]
    FROM [dbo].[vw_Raw_Data] WHERE [dbo].[vw_Raw_Data].RD_GUID_ID = 433

CREATE TABLE #TempTable(
 RowNum int,
 DenseRank int,
 ROI1_New NVARCHAR(MAX))

OPEN @Cursor;
FETCH NEXT FROM @Cursor INTO @DenseRank, @RD_ROI1_minus_RD_ROI3;
SET  @DenseRankPrevious = @DenseRank;
WHILE @@FETCH_STATUS = 0
BEGIN

    IF @DenseRankPrevious = @DenseRank
    SET @RowNum = @RowNum + 1;
    ELSE
    BEGIN
    SET @RowNum = 0;
    SET @RowNum = @RowNum + 1;
    SET @DenseRankPrevious = @DenseRank;
    END

    INSERT INTO #TempTable 
    SELECT @RowNum, @DenseRank, @RD_ROI1_minus_RD_ROI3 ;
    FETCH NEXT FROM @Cursor INTO @DenseRank, @RD_ROI1_minus_RD_ROI3;
END

CLOSE @Cursor;
DEALLOCATE @Cursor;

    SELECT * FROM #TempTable 
    DROP TABLE #TempTable

上面的代码给出了以下结果

- 1   1   178.409
- 2   1   173.23
- 3   1   164.867
- 4   1   165.52
- 5   1   153.351
- 6   1   160.773
- 7   1   157.694

而不是预期的以下内容。

- 1  1  178,409039893888
- 2 1   173,230282624222
- 3 1   164,86654423018
- 4 1   165,52035506581
- 5 1   153,351290684624
- 6 1   160,773492500765
- 7 1   157,694316906438

知道这种四舍五入的原因吗？提前谢谢！

Answer 1

为什么要使用游标？

SELECT ROW_NUMBER() OVER (PARTITION BY DenseRank ORDER BY (SELECT NULL)) as rn,
       rd.*
FROM (SELECT DENSE_RANK() OVER (ORDER BY rd.RD_RF_ID) AS DenseRank, 
             RD_ROI1_minus_RD_ROI3
      FROM dbo.vw_Raw_Data rd
      WHERE rd.RD_GUID_ID = 433
     ) rd;

当Dense_Rank（）值增加时重置Row_Number（）值

1 个答案: