DB query optimization?

Question

SQL query optimization

I am writing a diploma and there is a subsection - Optimization of database queries.
I'm new to this issue, so tell me or tell me where to read about the question "creating complex queries based on simple ones in the context of optimization."

Answer 1

SQL. Complete Guide
This book has enough material for a general understanding of your question, I'm very pleased with it, I learned a lot. You may have a diploma associated with the database, it will be very useful.
More - Query Optimization in SQL Server 2008 R2