What is a suitable workshop or simulator for pumping work with requests to choose?

Question

IT education

Lots of database stuff. There is also documentation on sql queries. I would like to increase my level of knowledge in this area to the pros. I studied the basic concepts at the institute and in practice for many years, but I didn’t have to do this in order to optimize very serious queries and everything that is needed for the pros.

Advise a simulator or other material that would allow you to improve your skills. Fortunately, there are many of them in the public domain, but I would like verified materials.

I expect to see answers like "I knew sql queries, but when it became necessary to improve my level, this helped me ...."

Please, without referring to the official doc.

Answer 1

You upgrade to a pro at work. No simulator will ever teach you combat skills.
It's like googling "how to swim" and when your grandfather throws you into the river from a boat.