UFN_SCHOOL_NAMEISUNIQUE

CREATE function dbo.UFN_SCHOOL_NAMEISUNIQUE
    (
        @ID uniqueidentifier
    )
returns int
as begin
    -- do work here and return a value

    declare @retval int;
    set @retval = 1;

    if ((exists (select CONSTITUENT.ID
         from dbo.CONSTITUENT
                   inner join SCHOOL
                       on CONSTITUENT.ID = SCHOOL.ID
                 where (CONSTITUENT.KEYNAME = (select CONSTITUENT2.KEYNAME 
                                         from dbo.CONSTITUENT AS CONSTITUENT2 
                                                                                 where CONSTITUENT2.ID = @ID)) and 
                       (CONSTITUENT.ID <> @ID))))
        set @retval = 0;

    return @retval;
end