Question

In a sqlserver table of 200,000 plus records, i need help with faster concat of some columns data grouped by other columns. For example, sample data and expected results is shown below.

Here i need to concat the last columns ColumnA, ColumnB, ColumnC as pipe-delimited string, for the combination of these four like :

where KeyNumber=@strKeyNumber  and  Action=@strAction  and  Type=@strType  and  Code=@strCode

These four are the distinct combination.

I coded for this using t-sql STUFF function, but it is too slow. I also coded differently with while loop, but even that is too slow.

So i need help with getting a faster result.

The data in those columns A, B, C are long strings, so the concatenated string should be of type nvarchar(max).

Original data in table (duplicates can be there in some columns):

ID  KeyNumber   Action  Type    Code    ColumnA     ColumnB     ColumnC  
1   1111111111  AC1     TYPE1   CODE1   ValueA1     ValueB1     ValueC1 
2   1111111111  AC1     TYPE1   CODE1   ValueA2     ValueB2     ValueC2 
3   1111111111  AC1     TYPE1   CODE1   ValueA2     ValueB2     ValueC3 
4   1111111111  AC1     TYPE1   CODE1   ValueA3     ValueB3     ValueC4
5   2222222222  AC2     TYPE2   CODE2   ValA1       ValB1       ValC1   
6   2222222222  AC2     TYPE2   CODE2   ValA2       ValB2       ValC2
7   2222222222  AC2     TYPE2   CODE2   ValA3       ValB3       ValC3
8   2222222222  AC2     TYPE2   CODE2   ValA4       ValB4       ValC4
9   2222222222  AC2     TYPE2   CODE2   ValA4       ValB5       ValC4   

Need the result data into a new table like below (duplicate values in above table should not be repeated here):

ID  KeyNumber   Action  Type    Code    ColumnA                 ColumnB                         ColumnC  
1   1111111111  AC1     TYPE1   CODE1   ValueA1|ValueA2|ValueA3 ValueB1|ValueB2|ValueB3         ValueC1|ValueC2|ValueC3|ValueC4 
2   2222222222  AC2     TYPE2   CODE2   ValA1|ValA2|ValA3|ValA4 ValB1|ValB2|ValB3|ValB4|ValB5   ValC1|ValC2|ValC3|ValC4 

Answer 1

You can check this one:

DECLARE @Table TABLE
(
    ID BIGINT,
    Keynumber BIGINT,
    [Action] CHAR(3),
    [Type] CHAR(5),
    Code CHAR(5),
    ColumnA NVARCHAR(MAX),
    ColumnB NVARCHAR(MAX),
    ColumnC NVARCHAR(MAX)
)

INSERT INTO @TABLE(ID,Keynumber,[Action],[Type],Code,ColumnA,ColumnB,ColumnC)
VALUES   (1,1111111111,'AC1','TYPE1','CODE1','ValueA1','ValueB1','ValueC1') 
        ,(2,1111111111,'AC1','TYPE1','CODE1','ValueA2','ValueB2','ValueC2')
        ,(3,1111111111,'AC1','TYPE1','CODE1','ValueA2','ValueB2','ValueC3')
        ,(4,1111111111,'AC1','TYPE1','CODE1','ValueA3','ValueB3','ValueC4')
        ,(5,2222222222,'AC2','TYPE2','CODE2','ValA1','ValB1','ValC1')
        ,(6,2222222222,'AC2','TYPE2','CODE2','ValA2','ValB2','ValC2')
        ,(7,2222222222,'AC2','TYPE2','CODE2','ValA3','ValB3','ValC3')
        ,(8,2222222222,'AC2','TYPE2','CODE2','ValA4','ValB4','ValC4')
        ,(9,2222222222,'AC2','TYPE2','CODE2','ValA4','ValB5','ValC4')

SELECT   Keynumber
        ,[Action]
        ,[Type]
        ,Code
        ,(
             SELECT  ColumnA AS [text()]
             FROM    @Table TableOne
             WHERE    TableOne.Keynumber = TableTwo.Keynumber and  TableOne.[Action] = TableTwo.[Action] and  TableOne.[Type] = TableTwo.[Type]
             ORDER BY TableOne.ColumnA
             FOR XML PATH(''), TYPE
        ).value('/', 'NVARCHAR(MAX)') AS ColumnA
        ,(
             SELECT  ColumnB AS [text()]
             FROM     @Table TableOne
             WHERE    TableOne.Keynumber = TableTwo.Keynumber and  TableOne.[Action] = TableTwo.[Action] and  TableOne.[Type] = TableTwo.[Type]
             ORDER BY TableOne.ColumnB
             FOR XML PATH(''), TYPE
        ).value('/', 'NVARCHAR(MAX)') AS ColumnB
        ,(
            SELECT   ColumnC AS [text()]
            FROM     @Table TableOne
            WHERE    TableOne.Keynumber = TableTwo.Keynumber and  TableOne.[Action] = TableTwo.[Action] and  TableOne.[Type] = TableTwo.[Type]
            ORDER BY TableOne.ColumnC
            FOR XML PATH(''), TYPE
        ).value('/', 'NVARCHAR(MAX)') AS ColumnC

FROM(
        SELECT  DISTINCT Keynumber,[Action],[Type],Code
        FROM    @Table
    ) TableTwo

Also, I am not sure what method of string concatenation you are using. You can check this site for other techniques:

http://www.simple-talk.com/sql/t-sql-programming/concatenating-row-values-in-transact-sql/