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

Alexander Farber <alexander.farber@xxxxxxxxx> · Tue, 16 Nov 2010 17:23:16 +0100

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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