Replace values in a CSV string

Question

I have a list of products in comma separated fashion and since the item list was replaced with new product items, I am trying to modify this CSV list with new product item list.

Answer 1

Convert your comma separated list to XML. Use a numbers table, XQuery and position() to get the separate ID's with the position they have in the string. Build the comma separated string using the for xml path('') trick with a left outer join to #tempprod and order by position().

;with C as
(
  select T.id,
         N.number as Pos,
         X.PList.value('(/i[position()=sql:column("N.Number")])[1]', 'int') as PID
  from @tmp as T
    cross apply (select cast(''+replace(plist, ',', '')+'' as xml)) as X(PList)
    inner join master..spt_values as N
      on N.number between 1 and X.PList.value('count(/i)', 'int')
  where N.type = 'P'  
)
select C1.id,
       stuff((select ','+cast(coalesce(T.newid, C2.PID) as varchar(10))
              from C as C2
                left outer join @tmpprod as T
                  on C2.PID = T.oldid
              where C1.id = C2.id
              order by C2.Pos
              for xml path(''), type).value('.', 'varchar(max)'), 1, 1, '')
              
from C as C1
group by C1.id

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