Book Image

Mastering PostgreSQL 9.6

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 9.6

By: Hans-Jürgen Schönig

Overview of this book

PostgreSQL is an open source database used for handling large datasets (Big Data) and as a JSON document database. It also has applications in the software and web domains. This book will enable you to build better PostgreSQL applications and administer databases more efficiently. We begin by explaining the advanced database design concepts in PostgreSQL 9.6, along with indexing and query optimization. You will also see how to work with event triggers and perform concurrent transactions and table partitioning, along with exploring SQL and server tuning. We will walk you through implementing advanced administrative tasks such as server maintenance and monitoring, replication, recovery and high availability, and much more. You will understand the common and not-so-common troubleshooting problems and how you can overcome them. By the end of this book, you will have an expert-level command of the advanced database functionalities and will be able to implement advanced administrative tasks with PostgreSQL.
Table of Contents (14 chapters)
Free Chapter
PostgreSQL Overview

Utilizing windowing functions and analytics

After discussing ordered sets, it is time to take a look at windowing functions. Aggregates follow a fairly simple principle: take many rows and turn them into fewer, aggregated rows. A windowing function is different. It compares the current row with all rows in the group. The number of rows returned does not change.

Here is an example:

test=# SELECT avg(production) FROM t_oil; 
(1 row)

test=# SELECT country, year, production, consumption, avg(production) OVER ()
FROM t_oil
country | year | production | consumption | avg
USA | 1965 | 9014 | 11522 | 2607.5139
USA | 1966 | 9579 | 12100 | 2607.5139
USA | 1967 | 10219 | 12567 | 2607.5139
USA | 1968 | 10600 | 13405 | 2607.5139
(4 rows)

The average...