SQL

Ready -made recipes for solving practical problems when working with the Oracle, DB2, SQL Server, MySQL and PostgreSQL DBMS. The extraction of records from tables, sorting the results of queries, the principles of working with several tables, processing requests with metadata are described. It is described about how to search for data by SQL by means of reports and formatting resulting sets, work with hierarchical requests. The use of window functions, generalized tabular expressions (VSK), data collection, the formation of histograms, current sums and osumm, aggregation of a sliding range of values ​​is considered. The circuit of the line and its syntactic analysis on the symbols are described, and methods for simplifying the calculations inside the line are given. The second edition takes into account all changes in the syntax and architecture of current SQL implementations