The SQL language (Structured Query Language) is an effective tool for working with tables in relational databases. It allows for selecting and sorting records, performing calculations, summarizing, and joining multiple data tables. With SQL, it is also possible to add, modify, and delete records in a table, change their structure, and create new tables. The book includes commonly used basic parts of SQL that are common across all database systems. It covers deviations of common systems from the SQL standard to ensure universal applicability (not oriented towards a specific database system). Common systems include Access, MS SQL Server, MySQL, PostgreSQL, and Visual Fox Pro. Attention is also given to object-relational mapping. Each chapter is always supplemented with a series of examples for independent solutions. Files needed to work on examples in SQL Server and MySQL databases can be found on the Grada publishing website (www.grada.cz). After mastering the book, anyone will be able to obtain simple reports from the database, sort them by various criteria, and filter them based on simple conditions. The publication can also be useful for website creators or advanced spreadsheet users.
