What to read on optimizing SQL queries?

Question

MySQL

Started working on the project, PostgreSQL 9.4 base. The first task is to review and optimize queries, search for unnecessary and duplicate queries.
Interested in a manual, book or article with practical examples on optimizing SQL queries, what are the pitfalls for aggregate functions of the COUNT type on large tables, how to correctly create complex indexes on several fields, how to read the query execution plan.
A special moment is how to work with tables that work like a log, they are constantly growing, sampling on them is getting slower, and if you need to do a JOIN with other tables of such a large table? Of course, you can make separate requests, and then merge them into an array, but the right approach is of interest.

Answer 1

For mysql, I recommend progbook.ru/bd/mysql/1182-shvarc-mysql-optimizaciy...