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Learning PostgreSQL 10

Learning PostgreSQL 10

By : Juba, Volkov
2.3 (6)
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Learning PostgreSQL 10

Learning PostgreSQL 10

2.3 (6)
By: Juba, Volkov

Overview of this book

PostgreSQL is one of the most popular open source databases in the world, supporting the most advanced features included in SQL standards. This book will familiarize you with the latest features released in PostgreSQL 10. We’ll start with a thorough introduction to PostgreSQL and the new features introduced in PostgreSQL 10. We’ll cover the Data Definition Language (DDL) with an emphasis on PostgreSQL, and the common DDL commands supported by ANSI SQL. You’ll learn to create tables, define integrity constraints, build indexes, and set up views and other schema objects. Moving on, we’ll cover the concepts of Data Manipulation Language (DML) and PostgreSQL server-side programming capabilities using PL/pgSQL. We’ll also explore the NoSQL capabilities of PostgreSQL and connect to your PostgreSQL database to manipulate data objects. By the end of this book, you’ll have a thorough understanding of the basics of PostgreSQL 10 and will have the necessary skills to build efficient database solutions.
Table of Contents (17 chapters)
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Window functions


Apart from grouping and aggregation, PostgreSQL provides another way to perform computations based on the values of several records. It can be done using Window functions. Grouping and aggregation implies the output of a single record for every group of input records. Window functions can do similar things, but they are executed for every record, and the number of records in the output and the input is the same:

GROUP BY and window functions

In the preceding diagram, the rectangles represent the records of a table. Let's assume that the color of the rectangles indicates the value of a field used to group the records. When GROUP BY is used in a query, each distinct value of that field will create a group and each group will become a single record in the results of the query. This was explained in Chapter 05, SQL Language. Window functions provide access to the values of all the records of the group (which is called a partition in this case), although the number of records in...

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