Here i upload various solutions from sql practice websites:
- sqlzoo.net - ✔️
- windowfunctions.com - ✔️
- learndb.ru - ✔️
- sql-academy.org - ✔️
- sqlpad.io - ✔️
- pgexercises - ✔️
- stratascratch - ✔️
- Интерактивный тренажер по SQL степик, stepik https://stepik.org/course/63054/syllabus ✔️