Hvordan får man den tilsvarende kommaseparerede tekst til en streng af kommaseparerede koder?

Der kan være enklere løsninger til at gøre dette, men her er én måde.

Tabelstruktur

create table Locations(LocationID int, Location varchar(50))
create table OtherTable(ID int, Locations varchar(max))

Testdata

insert into Locations values(1, 'Location <1>')
insert into Locations values(2, 'Location <2>')
insert into Locations values(3, 'Location <3>')
insert into Locations values(4, 'Location <4>')
insert into Locations values(5, 'Location <5>')

insert into OtherTable values (1, '')
insert into OtherTable values (2, '2')
insert into OtherTable values (3, '1, 3 ,5')

Forespørgsel

;with cte as
(
  select 
    T.ID,
    coalesce(L.Location, '') as Location
  from OtherTable as T
    cross apply
      (select cast('<r>'+replace(T.Locations, ',', '</r><r>')+'</r>' as xml)) LocXML(XMLCol)
    cross apply
      LocXML.XMLCol.nodes('r') LocID(IDCol) 
    left outer join Locations as L
      on L.LocationID = LocID.IDCol.value('.', 'int')
)
select
  C1.ID,
  stuff((select ', '+C2.Location
         from cte as C2 
         where C1.ID = C2.ID
         for xml path(''), type).value('text()[1]', 'nvarchar(max)'), 1, 2, '') as Locations
from cte as C1
group by C1.ID

Resultat

ID  Locations
--- ----------------------------------------
1   
2   Location <2>
3   Location <1>, Location <3>, Location <5>