Skip to Content
PostgreSQL 10 Administration Cookbook - Fourth Edition
book

PostgreSQL 10 Administration Cookbook - Fourth Edition

by Simon Riggs, Gianni Ciolli
May 2018
Intermediate to advanced content levelIntermediate to advanced
576 pages
30h 25m
English
Packt Publishing
Content preview from PostgreSQL 10 Administration Cookbook - Fourth Edition

How it works…

Moving from the integer to the date type uses a complex USING expression. Let's break that down step by step so that we can see why, as follows:

postgres=# ALTER TABLE birthdayALTER COLUMN dob SET DATA TYPE dateUSING date(to_date(dob::text, 'YYMMDD') -      (CASE WHEN dob/10000 BETWEEN 16 AND 69      THEN interval '100 years'      ELSE interval '0' END));

First, we can't move directly from integer to date. We need to convert it to text and then to date. The dob::text statement means cast to text.

Once we have text, we use the to_date() function to move to a date type.

This is not enough; our starting data was 690926, which we presume is a date in the YYMMDD format. When PostgreSQL converts this data to a date, it assumes that the two-digit ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

PostgreSQL 13 Cookbook

PostgreSQL 13 Cookbook

Vallarapu Naga Avinash Kumar
PostgreSQL 9 Administration Cookbook - Second Edition

PostgreSQL 9 Administration Cookbook - Second Edition

Simon Riggs, GIANNI CIOLLI, Hannu Krosing, Gabriele Bartolini

Publisher Resources

ISBN: 9781788474924Supplemental Content