SQL. A Beginner's Course.

The book outlines the fundamentals of working with relational databases and the practical application of SQL in the most in-demand scenarios.

It discusses the principles of data storage, table structure, and methods of retrieving information. It provides a detailed description of selection, filtering, sorting, grouping, and aggregation operations, working with text and numeric data, date processing, and the use of expressions and conditions. The mechanisms of joining tables, the features of various types of JOIN, and ways to combine selections are thoroughly examined. 

It describes the creation and modification of tables, setting constraints, indexes, and auto-increment fields, as well as the principles of adding, updating, and deleting data.

Reference information is provided on data types, the order of query execution, plans and statistics, transactions and ACID requirements, as well as the basics of client-server architecture.