CREATE TABLE meso ( mes_kwdikos serial PRIMARY KEY, mes_onoma varchar(16) UNIQUE, mes_typos varchar(16), CHECK (mes_typos in ('TV', 'radio', 'efimerida', 'internet')));CREATE TABLE diafimisi ( diaf_ekth_kwdik integer REFERENCES ekthesi(ekth_kwdikos) ON DELETE RESTRICT, diaf_mes_kwdik integer REFERENCES meso(mes_kwdikos) ON DELETE RESTRICT, diaf_date date, diaf_kostos money, PRIMARY KEY (diaf_ekth_kwdik, diaf_mes_kwdik, diaf_date));create temporary view diafimisi_meso (typos, onoma, kostos) as select mes_typos, mes_onoma, diaf_kostos from diafimisi, meso where diaf_mes_kwdik = mes_kwdikos;select typos, onoma, kostosfrom diafimisi_mesowhere (typos, kostos) in (select typos, max(kostos) from diafimisi_meso group by typos);-- orselect mes_typos, mes_onoma, diaf_kostosfrom diafimisi inner join meso on diaf_mes_kwdik = mes_kwdikoswhere (mes_typos, diaf_kostos) in (select mes_typos, max(diaf_kostos) from diafimisi inner join meso on diaf_mes_kwdik = mes_kwdikos group by mes_typos);-- or-- 01:31 < olspookishmagus> ara mporeis na kaneis prwta sort ton pinaka pros to megista tou ka8e typou-- 01:31 < olspookishmagus> kai meta apo to join na pareis ta onomata-- 01:31 < olspookishmagus> ta megista*