Re: Using random() in update produces same random value for all

Поиск

Список

Период

Сортировка

От	Ken Tanzer
Тема	Re: Using random() in update produces same random value for all
Дата	14 января 2018 г. 16:24:04
Msg-id	CAD3a31Wkji3HCPxcRDdA6P6xHjjURV-YP_Z6wYitqSpc2G0e4g@mail.gmail.com обсуждение исходный текст
Ответ на	Using random() in update produces same random value for all (Alex Magnum <magnum11200@gmail.com>)
Список	pgsql-general

Дерево обсуждения

On Sun, Jan 14, 2018 at 2:01 AM, Alex Magnum <magnum11200@gmail.com> wrote:

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.

I verified this with a SELECT, not an UPDATE, but I think leaving this as a simple expression will do what you want. Just leave out the SELECT:

UPDATE table

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

Cheers,

Ken