Hey there! It sounds like you’ve already put in solid work grinding through sql-ex.ru and codefights.com—awesome job sticking with SQL practice for a full year! If you’re looking to take your query writing to the next level, here are some top-tier, practical resources I’d recommend:

• LeetCode SQL Section
  This platform has a massive library of SQL problems sorted by difficulty (easy to hard) and topic—think basic SELECTs, joins, subqueries, window functions, and even recursive CTEs. Each problem comes with a discussion thread where you can compare your solution with others, pick up optimization tricks, and learn alternative approaches from the community.

• HackerRank SQL Challenges
  Organized into structured skill tracks (like aggregate functions, database design, and advanced queries), HackerRank lets you practice in a targeted way. They also offer certification tests that you can add to your resume, which is a nice bonus if you’re looking to validate your skills for employers.

• Mode Analytics Interactive SQL Exercises
  Mode uses real-world datasets (like e-commerce or analytics data) for their interactive tutorials and exercises. You can write queries directly in the browser and see results instantly, which is perfect for learning how to handle messy, unstructured data that you’d encounter in actual jobs.

• SQLZoo
  A classic, no-frills resource with step-by-step lessons and practice problems covering everything from fundamentals to advanced topics like triggers, stored procedures, and transaction management. It’s great for reinforcing core concepts and filling in any knowledge gaps you might have.

• DataLemur
  Focused on interview-style SQL problems, DataLemur features questions modeled after real tech company interviews (Google, Amazon, Meta, etc.). If you’re prepping for data analyst or data science roles, this is a must-use resource to get comfortable with the types of problems employers ask.

• PostgreSQL Exercises
  If you’re specializing in PostgreSQL, this site has a huge collection of exercises tailored to the database’s unique features—like array functions, JSON handling, and advanced indexing. It’s a deep dive into the specifics of one of the most popular open-source databases out there.

Beyond structured platforms, don’t sleep on real-world datasets! Grab public datasets (from government portals or open data repositories) and brainstorm your own questions to answer. Solving self-directed problems with actual data is one of the best ways to build practical, job-ready SQL skills.

内容的提问来源于stack exchange，提问作者Zampanò