SQL trainers?

Question

SQL

Do not prompt articles, books, interactive sites to fill your hand in queries. I haven't programmed for a long time, lately I've only been doing typesetting after a long break. I remember the commands, normalization, I just need to practice for a couple of days, while I completed 40 tasks on sql-ex.ru, I also think there are interesting tasks on codewars, though nothing has gone through sql there yet .
Interested in the format of the finished database and tasks for the sample or about the approach itself, where TK is given and you should already form tables.

Answer 1

try to pass sql-ex.ru to the end. if you can. and then try to come up with at least a dozen of the best queries in terms of cost. if you can. this is enough for you to "fill your hand." I guarantee.
once there were 138 tasks and the last one, about Mullah Omar, was solved by a dozen people. By the way, I didn't succeed :(