UFN_CLIENTUSERID_GET_BY_CONSTITUENT

create function [dbo].[UFN_CLIENTUSERID_GET_BY_CONSTITUENT]
(  
 @CONSTITUENTID uniqueidentifier  
)   
returns int   
as  
begin  
 declare @ID int = null;  

 select top 1 @ID = CU.ID 
 from dbo.CONSTITUENT C(nolock)  
 inner join dbo.BackOfficeSystemPeople BOSP(nolock)  
  on BOSP.BackofficeRecordID = C.SEQUENCEID and BOSP.BackOfficeSystemID = 0   
 inner join dbo.BackOfficeSystemUsers BOSU(nolock)  
  on BOSU.BackofficePeopleID = BOSP.ID and BOSU.[CURRENT] = 1  
 inner join dbo.ClientUsers CU(nolock)  
  on CU.ID = bosu.ClientUsersID and CU.Deleted = 0   
  and C.ID = @CONSTITUENTID  

 return @ID;  
end