UFN_SITEID_MAPFROM_SOURCECODEITEMID

create function [BBDW].[UFN_SITEID_MAPFROM_SOURCECODEITEMID]
  (  
    @SOURCECODEITEMID uniqueidentifier  
  )   
  returns uniqueidentifier
    as  

    begin
      declare @ID uniqueidentifier;
      select @ID = case when ms.[SITESYSTEMID] <> '00000000-0000-0000-0000-000000000000' then ms.[SITESYSTEMID] else null end 
      from BBDW.[DIM_MARKETINGSOURCECODE] ms
      inner join BBDW.[DIM_MARKETINGSOURCECODEPART] mp on ms.[MARKETINGSOURCECODEDIMID] = mp.[MARKETINGSOURCECODEDIMID]
      where mp.[MARKETINGSOURCECODEPARTSYSTEMID] = @SOURCECODEITEMID
      return @ID
    end