2022
https://proglib.io/p/osnovnye-sql-komandy-i-zaprosy-s-primerami-kotorye-dolzhen-znat-kazhdyy-razrabotchik-2022-04-14
https://proglib.tech/p/osnovnye-sql-komandy-i-zaprosy-s-primerami-kotorye-dolzhen-znat-kazhdyy-razrabotchik-2022-04-14