delete from tb_rel 
where
    id_rel in (
        select id_rel
        from tb_rel 
        where
            org in (
                select
                    org
                from tb_rel
                where
                    coalesce(org, '') <> ''
                group by
                    org
                having
                    count(*) > 1
            )
    ) and coalesce(cust, false);


delete from tb_rel where sit = 'I';