UFN_SITEID_MAPFROM_GLACCOUNTID

CREATE function dbo.UFN_SITEID_MAPFROM_GLACCOUNTID
(
@GLACCOUNTID uniqueidentifier
)
returns table
as  
return
    select IsNull(PDACCOUNTSYSTEMSITE.SITEID, '00000000-0000-0000-0000-000000000000') as SITEID
    from dbo.GLACCOUNT 
    left outer join dbo.PDACCOUNTSYSTEMSITE on PDACCOUNTSYSTEMSITE.PDACCOUNTSYSTEMID = GLACCOUNT.PDACCOUNTSYSTEMID
    where GLACCOUNT.ID = @GLACCOUNTID
        union all
    select null as SITEID
    from dbo.GLACCOUNT 
    left outer join dbo.PDACCOUNTSYSTEM on PDACCOUNTSYSTEM.ID = GLACCOUNT.PDACCOUNTSYSTEMID
    where GLACCOUNT.ID = @GLACCOUNTID and PDACCOUNTSYSTEM.ISDEFAULT = 1