4:
select id_klienta, castka from klient join meridlo using(id_klienta) join odecty using(ozn_meridla) join obdobi using (id_obdobi)
where
id_obdobi=1
having castka>=avg(castka)
4:
select id_klienta, castka from klient join meridlo using(id_klienta) join odecty using(ozn_meridla) join obdobi using (id_obdobi)
where
id_obdobi=1
having castka>=avg(castka)