>>>>create cursor Customer (c_id I) >>>> insert into Customer values(1) >>>> insert into Customer values(2) >>>> >>>> Create cursor Orders( ord_id I, Ord_c_id I ) >>>> >>>> insert into Orders values (22, 2) >>>> insert into Orders values (24, 2) >>>> >>>> && find customers without order(s) >>>> >>>> && (1) >>>> select c_id ; >>>> from Customer ; >>>> into cursor tmp1 ; >>>> where ( not exists ; >>>> (select * from Orders where (Ord_c_id = c_id) ) ; >>>> ); >>>> >>>> brow >>>> >>>> && (2) left join, with having >>>> select c_id, ; >>>> ord_id ; >>>> from Customer ; >>>> left join Orders on (Ord_c_id = c_id) ; >>>> into cursor tmp2 ; >>>> having ( ord_id is null ) >>>> >>>> brow >>>> >>>> >>>> && (3) left join, with where >>>> select c_id, ; >>>> ord_id ; >>>> from Customer ; >>>> left join Orders on (Ord_c_id = c_id) ; >>>> into cursor tmp3 ; >>>> where ( ord_id is null ) >>>> >>>> brow >>>>>>>