Re: Selecting top N percent of records.

>
> OK, so you want a median-style "sort them in descending order and count down
> until you've selected the first 10% of rows" approach? In other words,
> values in the 90th percentile of the distribution?
>
> Try this. Given table "x" with single integer column "y", obtain rows of x
> in the 90th percentile of y:
>
> select ranked.y FROM (select percent_rank() over (order by y desc) as pc, y
> from x) AS ranked WHERE pc <= 0.1;
>
> or:
>
> select ranked.y from (select ntile(10) over (order by y desc) as pc, y from
> x) AS ranked WHERE pc = 1;
>

Thanks I will look into the window functions. I haven't used them
before so thanks for the tip.