sql server split comma separated values into columns

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青春惊慌失措
青春惊慌失措 2020-12-19 07:30

I trying to split the csv to individual columns

SAMPLE DATA

PAR_COLUMN  PERIOD  VALUE       mul_query
----------  ------  ---------         


        
3条回答
  •  星月不相逢
    2020-12-19 08:16

    You can roll your own string splitting function as detailed in great depth here by Jeff Moden.

    For posterity purposes, the final code is:

    CREATE FUNCTION [dbo].[DelimitedSplit8K]
    --===== Define I/O parameters
            (@pString VARCHAR(8000), @pDelimiter CHAR(1))
    --WARNING!!! DO NOT USE MAX DATA-TYPES HERE!  IT WILL KILL PERFORMANCE!
    RETURNS TABLE WITH SCHEMABINDING AS
     RETURN
    --===== "Inline" CTE Driven "Tally Table" produces values from 1 up to 10,000...
         -- enough to cover VARCHAR(8000)
      WITH E1(N) AS (
                     SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
                     SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
                     SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
                    ),                          --10E+1 or 10 rows
           E2(N) AS (SELECT 1 FROM E1 a, E1 b), --10E+2 or 100 rows
           E4(N) AS (SELECT 1 FROM E2 a, E2 b), --10E+4 or 10,000 rows max
     cteTally(N) AS (--==== This provides the "base" CTE and limits the number of rows right up front
                         -- for both a performance gain and prevention of accidental "overruns"
                     SELECT TOP (ISNULL(DATALENGTH(@pString),0)) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
                    ),
    cteStart(N1) AS (--==== This returns N+1 (starting position of each "element" just once for each delimiter)
                     SELECT 1 UNION ALL
                     SELECT t.N+1 FROM cteTally t WHERE SUBSTRING(@pString,t.N,1) = @pDelimiter
                    ),
    cteLen(N1,L1) AS(--==== Return start and length (for use in substring)
                     SELECT s.N1,
                            ISNULL(NULLIF(CHARINDEX(@pDelimiter,@pString,s.N1),0)-s.N1,8000)
                       FROM cteStart s
                    )
    --===== Do the actual split. The ISNULL/NULLIF combo handles the length for the final element when no delimiter is found.
     SELECT ItemNumber = ROW_NUMBER() OVER(ORDER BY l.N1),
            Item       = SUBSTRING(@pString, l.N1, l.L1)
       FROM cteLen l
    

    Once you have this function, you can pull out the relevant data using a pivot table:

    select PAR_COLUMN
            ,PERIOD
            ,VALUE
            ,mul_query
            ,[1]
            ,[2]
            ,[3]
            ,[4]
    from(select f.PAR_COLUMN
                ,f.PERIOD
                ,f.VALUE
                ,f.mul_query
                ,s.ItemNumber
                ,s.Item
        from @finals f
            cross apply dbo.DelimitedSplit8K(f.mul_query,'*') s
        ) as d
    pivot
    (
    max(Item)
    for ItemNumber in([1],[2],[3],[4])
    ) as pvt
    

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