fnPasswordLastChanged

            create FUNCTION [dbo].[fnPasswordLastChanged]
            (    
            @UserID        int
            )
            RETURNS datetime
            AS
            BEGIN
                DECLARE @dateUsed datetime
                select top 1 @dateUsed = DateUsed from ClientUserPasswordHistory where UserID = @UserID order by DateUsed Desc
                if @dateUsed is null
                    select top 1 @dateUsed = UpdateDate from ClientUsers where ID = @UserID;

                RETURN coalesce(@dateUsed, getutcdate())
            END