join comma delimited data column

Question

my table1 is :

T1

col1    col2
 C1     john
 C2     alex
 C3     piers
 C4     sara

and so table 2:

T2

Answer 1

First write a table value function for split col2 on tbl2.

CREATE FUNCTION [dbo].[Split](@String varchar(100), @Delimiter char(1))       
returns @temptable TABLE (items VARCHAR(5))       
as       
begin       
    declare @idx int       
    declare @slice VARCHAR(5)

    select @idx = 1       
        if len(@String)<1 or @String is null  return       

    while @idx!= 0       
    begin       
        set @idx = charindex(@Delimiter,@String)       
        if @idx!=0       
            set @slice = left(@String,@idx - 1)       
        else       
            set @slice = @String       

        if(len(@slice)>0)  
            insert into @temptable(Items) values(@slice)       

        set @String = right(@String,len(@String) - @idx)       
        if len(@String) = 0 break       
    end   
return       
end  

Go

;WITH    SplitList
          AS ( SELECT   T2.Col1 ,
                        T1.Col2
               FROM     T2
                        CROSS APPLY dbo.Split(T2.Col2, ',') S
                        INNER JOIN T1 ON T1.Col1 = S.Items
             )
    SELECT  T2.Col1 ,
            STUFF(( SELECT  ', ' + SplitList.Col2
                    FROM    SplitList
                    WHERE   SplitList.Col1 = T2.Col1
                  FOR
                    XML PATH('')
                  ), 1, 2, '')
    FROM    T2