Convert comma separated string into XML with sequence number in SQL Server 2005

Question

I am using SQL Server 2005. I have the following:

DECLARE @list NVARCHAR(MAX)
DECLARE @xml XML

SET @list = 'aa,bb,cc,dd,ee'

I would like to fill in @xml with data from the @list with the following format:

<row seq="1" col1="aa" />
<row seq="2" col1="bb" />
<row seq="3" col1="cc" />
<row seq="4" col1="dd" />

I tried to convert the @list into an XML string with the following:

SET @xml = '<row>' + REPLACE(@list, ',', '</row><row>') + '</row>'

and then tried to look for a FLWOR Expression in the @xml.query method that can add the sequence number for the rows, but I am out of luck as there is no let clause in SQL server 2005. Could anyone give me a hint/workaround? Thanks.

Answer 1

Here's a way using a split function...

DECLARE @list NVARCHAR(MAX)
DECLARE @xml XML

SET @list = 'aa,bb,cc,dd,ee'

;with cteSplit as(
    select * from dbo.DelimitedSplit8K(@list,',')),

cteFinal as(
select 
    '<row seq="' + cast(ItemNumber as varchar(64)) + '"  col1="' + Item + '" />' as Item
from cteSplit)

select Item from cteFinal --for XML AUTO

Here is the function which has proven to be a fast method of splitting strings:

CREATE FUNCTION [dbo].[DelimitedSplit8K] (@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
;
GO