Re: Counting boolean values (how many true, how many false)

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От maarten
Тема Re: Counting boolean values (how many true, how many false)
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Msg-id 1289926171.4363.81.camel@localhost
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Ответ на Counting boolean values (how many true, how many false)  (Alexander Farber <alexander.farber@gmail.com>)
Ответы Re: Counting boolean values (how many true, how many false)  (Thom Brown <thom@linux.com>)
Список pgsql-general
Hi,

sum doesn't like booleans, but it does like integers so:
sum(boolval::int) solves that problem for you.

SELECT id,sum(good::int + fair::int + nice::int) would get you a total
of the three for each row

good luck,
Maarten




On Tue, 2010-11-16 at 17:23 +0100, Alexander Farber wrote:
> Hello,
>
> if I have this table with 3 boolean columns:
>
> # \d pref_rate
>                  Table "public.pref_rep"
>    Column   |            Type             |   Modifiers
> ------------+-----------------------------+---------------
>  id         | character varying(32)       |
>  author     | character varying(32)       |
>  good       | boolean                     |
>  fair       | boolean                     |
>  nice       | boolean                     |
>  about      | character varying(256)      |
>  last_rated | timestamp without time zone | default now()
> Foreign-key constraints:
>     "pref_rate_author_fkey" FOREIGN KEY (author) REFERENCES pref_users(id)
>     "pref_rate_id_fkey" FOREIGN KEY (id) REFERENCES pref_users(id)
>
> - how can I please count the number of
> true's and false's for each column for a certain id?
> (to find that persons rating)
>
> I'm trying:
>
>    select sum(fair=true), sum(fair=false) from pref_rep;
>
> but sum() doesn't like a boolean as an argument.
>
> I've only come up with
>
>     select count(*) from pref_rep where fair=true and id='XXX';
>
> but this would mean I have to call this line 6 times? (2 x column).
>
> Thank you
> Alex
>


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