Видео с ютуба What Is Correct Syntax For Nested Group By Query

Расширенные агрегатные функции в SQL (GROUP BY, HAVING и WHERE)

Advanced SQL Query - 2 | Interview Question | Nested GROUP BY

Mastering SQL: The count(distinct) Command for Nested Group By Queries

GROUP BY and HAVING Clause in SQL

Как делать подзапросы в SQL с примерами

Nested Queries | SQL | Tutorial 18