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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 to do it…

You can add a new column to a table using this command:

ALTER TABLE mytableADD COLUMN last_update_timestamp TIMESTAMP WITHOUT TIME ZONE;

You can drop the same column using the following command:

ALTER TABLE mytableDROP COLUMN last_update_timestamp;

You can combine multiple operations when using ALTER TABLE, which then applies the changes in a sequence. This allows you to do a useful trick, which is to add a column unconditionally, using IF EXISTS, as follows:

ALTER TABLE mytableDROP COLUMN IF EXISTS last_update_timestamp,ADD COLUMN last_update_timestamp TIMESTAMP WITHOUT TIME ZONE;

Note that this will have almost the same effect as the following command:

UPDATE mytable SET last_update_timestamp = NULL;

However, ALTER TABLE

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Publisher Resources

ISBN: 9781788474924Supplemental Content