Re: PostgreSQL 9.1 : why is this query slow? - Mailing list pgsql-performance

"Kevin Grittner" <Kevin.Grittner@wicourts.gov> wrote:

> If you really want the intersection, perhaps:

Or maybe closer:

with x as
  (
    select
        word,
        count(*) as countall,
        count(case when filetype = 'f' then 1 else null end)
          as countf,
        count(case when filetype = 's' then 1 else null end)
          as counts,
        count(case when filetype = 'n' then 1 else null end)
          as countn
      from unique_words
      group by word
  )
select word, least(countf, counts, countn) from x
  where countf > 0 and counts > 0 and countn > 0
  order by word;

Cranked out rather quickly and untested.

-Kevin