Re: PostgreSQL needs percentage function

On Mon, Dec 18, 2017 at 6:23 AM, Nick Dro <postgresql(at)walla(dot)co(dot)il> wrote:

> Hi,
> Why PostgreSQL doesn't have build-in function to calculate percentage?
> somthing like percent(number,%
> for example:
> select percent(100,1) will calculate 1% of 100 = 1
> select percent(25,20) will calculate 20% of 25 = 5
>
> Seems like a nice addition to the math functions list:
> https://www.postgresql.org/docs/9.5/static/functions-math.html
>
> This is veryhelpull function, many uses percentage calculation in thier
> work and it will simplify the process. Percentage calculation is considered
> a basic math operation and I think postgresql should support it as a
> build-in function.
> Seems like easy to implment isn't it?
>

It's a bit trickier than that, because you';ll have to deal with integers,
real, double precision, etc. You may also want to deal with null values.
I found it more useful to write a function that displays X as a percentage
of Y, rounded to 1 digit to the right of the decimal point.
--
Mike Nolan