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Using random() in update produces same random value for all - Mailing list pgsql-general

From	Alex Magnum
Subject	Using random() in update produces same random value for all
Date	January 14, 2018 16:01:11
Msg-id	CA+cR4zde6SSaMfznJRgrM1zB2NYHjh6Uzn1ARXYW9_4sRvvUPA@mail.gmail.com Whole thread Raw
Responses	Re: Using random() in update produces same random value for all (Ken Tanzer <ken.tanzer@gmail.com>)
List	pgsql-general

Hi,

i am trying to update a table with some random dates but that does not seem to work.

UPDATE table

SET last_update=now()::date-(SELECT (random() * 5)::INTEGER + 1)

The updated field is always set to the same. Is there a way to make it random for every record?

I could run it through a function but I wonder if there is s simpler way.

Thanks for any help on this

Alex

From: Tom Lane
Date: 14 January 2018, 05:12:58
Subject: Re: psql format result as markdown tables

From: Ken Tanzer
Date: 14 January 2018, 16:24:04
Subject: Re: Using random() in update produces same random value for all