Something like this should work - (but is untested), and does require the extra
subquery, so there may be a more efficient way?
However, off the top of my head:
select a,b,c
from table
where
order by c desc
limit (select count(*)/10 from table where );
where c is the no of sales column
B
>
> 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
On 10/18/2010 08:06 AM, Tim Uckun wrote:
That is a bit problematic because it necessitates knowing the number
of rows total, and slow counting is an idiosyncrasy of postgres.
http://wiki.postgresql.org/wiki/Slow_Counting
To get the top 10%:
SELECT * FROM table LIMIT(SELECT (COUNT(*) * 0.1)::in
> That is a bit problematic because it necessitates knowing the number
> of rows total, and slow counting is an idiosyncrasy of postgres.
>
> http://wiki.postgresql.org/wiki/Slow_Counting
>
> To get the top 10%:
>
> SELECT * FROM table LIMIT(SELECT (COUNT(*) * 0.1)::integer FROM table)
I think I
On Mon, Oct 18, 2010 at 12:53 PM, Darren Duncan wrote:
> Tim Uckun wrote:
>>
>> Is there a way to select the top 10% of the values from a column?
>>
>> For example the top 10% best selling items where number of sales is a
>> column.
>
> The top 10% would be a variable number of records. Is that w
On 18 October 2010 00:33, Tim Uckun wrote:
> Is there a way to select the top 10% of the values from a column?
>
> For example the top 10% best selling items where number of sales is a column.
>
That is a bit problematic because it necessitates knowing the number
of rows total, and slow counting
Tim Uckun wrote:
Is there a way to select the top 10% of the values from a column?
For example the top 10% best selling items where number of sales is a column.
The top 10% would be a variable number of records. Is that what you want, or
would you rather, say, just see the top N items?
The
Is there a way to select the top 10% of the values from a column?
For example the top 10% best selling items where number of sales is a column.
Thanks.
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