Book Image

Learning PostgreSQL 11 - Third Edition

By : Salahaldin Juba, Andrey Volkov
Book Image

Learning PostgreSQL 11 - Third Edition

By: Salahaldin Juba, Andrey Volkov

Overview of this book

PostgreSQL is one of the most popular open source database management systems in the world, and it supports advanced features included in SQL standards. This book will familiarize you with the latest features in PostgreSQL 11, and get you up and running with building efficient PostgreSQL database solutions from scratch. Learning PostgreSQL, 11 begins by covering the concepts of relational databases and their core principles. You’ll explore the Data Definition Language (DDL) and commonly used DDL commands supported by ANSI SQL. You’ll also learn how to create tables, define integrity constraints, build indexes, and set up views and other schema objects. As you advance, you’ll come to understand Data Manipulation Language (DML) and server-side programming capabilities using PL/pgSQL, giving you a robust background to develop, tune, test, and troubleshoot your database application. The book will guide you in exploring NoSQL capabilities and connecting to your database to manipulate data objects. You’ll get to grips with using data warehousing in analytical solutions and reports, and scaling the database for high availability and performance. By the end of this book, you’ll have gained a thorough understanding of PostgreSQL 11 and developed the necessary skills to build efficient database solutions.
Table of Contents (18 chapters)

Advanced SQL techniques

In the following section, some other advanced SQL techniques will be introduced:

  • The DISTINCT ON clause, which helps to group records and take the first record for each group
  • Selecting sample data from a very big table
  • Set-returning functions, which are functions that return relations
  • LATERAL joins, which allow subqueries to reference each other
  • Advanced grouping techniques that can be used to generate reports
  • Some special aggregating functions

Selecting the first records

Quite often, it's necessary to find the first records based on some criteria. For example, let's take the car_portal database; suppose you need to find the earliest advertisement for each car_id in the advertisement table...