Прочитать:https://habr.com/ru/articles/305926/
Учить:https://codechick.io/tutorials/sqlhttps://stepik.org/course/63054/syllabus
Решать:https://sql-academy.org/ru/trainerhttps://www.sql-ex.ru/https://www.pgexercises.com/questions/basic/https://www.hackerrank.com/domains/sql
https://sqltest.online
Прочитать:
https://habr.com/ru/articles/305926/
Учить:
https://codechick.io/tutorials/sql
https://stepik.org/course/63054/syllabus
Решать:
https://sql-academy.org/ru/trainer
https://www.sql-ex.ru/
https://www.pgexercises.com/questions/basic/
https://www.hackerrank.com/domains/sql
https://sqltest.online