Re: Random function

How is this a performance related question?

On Tue, Mar 24, 2020 at 11:10 AM Luis Roberto Weck <
luisroberto(at)siscobra(dot)com(dot)br> wrote:

> However, I am getting the same result over mulitiple rows. This is a
> sample of the SQL I am using:
>
> select (select string_agg(random()::text,';')
> from pg_catalog.generate_series(1,3,1) )
> from generate_series(1,10,1)
>
> And I am getting something like:
>
> |string_agg |
> +--------------------------------------------------------------+
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
> |0.243969671428203583;0.692578794434666634;0.291524752043187618|
>
> If this is the expected output,

Yes, you've asked it to compute a value, assign it to a column, then
generate 10 rows of that value.

is there a way to always generate random
> numbers?
>

Don't use a scalar subquery in the main target list.

One possible answer:

select format('%s;%s;%s', random(), random(), random()) from
generate_series(1, 10)

David J.