From: | "Ow Mun Heng" <ow(dot)mun(dot)heng(at)wdc(dot)com> |
---|---|
To: | "Sam Mason" <sam(at)samason(dot)me(dot)uk>, <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Putting many related fields as an array |
Date: | 2009-05-12 12:06:25 |
Message-ID: | D1109E8B2FB53A45BDB60F8145905CE901CE35D3@wdmyexbe03.my.asia.wdc.com |
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Lists: | pgsql-general |
-----Original Message-----
From: pgsql-general-owner(at)postgresql(dot)org [mailto:pgsql-general-
On Tue, May 12, 2009 at 01:23:14PM +0800, Ow Mun Heng wrote:
>> | sum of count | sum_of_count_squared | qty | qty < 100 | qty < 500 |
>>
>>
>> I'm thinking of lumping them into 1 column via an array instead of into
>> 5 different columns. Not sure how to go about this, hence the email to
>> the list.
>The normal array constructor should work:
>
> SELECT ARRAY[MIN(v),MAX(v),AVG(v),STDEV(v)]
> FROM (VALUES (1),(3),(4)) x(v);
>
>Not sure why this is better than using separate columns though. Maybe a
>new datatype and a custom aggregate would be easier to work with?
The issue here is the # of columns needed to populate the table.
The table I'm summarizing has close to between 50 to 100+ columns, if the
1:5x is used as a yardstick, then the table will get awfully wide quickly.
I need to know how to do it first, then test accordingly for performance and
corner cases.
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