Tom Lane wrote:
> "Kevin Grittner" <kgrittn@mail.com> writes:
> > Pavel Stehule wrote:
> >> 2012/10/22 Tom Lane <tgl@sss.pgh.pa.us>:
> >>> Perhaps it would be close enough to what you want to use DISTINCT ON:
> >>> contrib_regression=# explain select distinct on( t <-> 'foo') *,t <-> 'foo' from test_trgm order by t <-> 'foo'
limit10;
>
> >> good tip - it's working
>
> > If two or more values happen to be at exactly the same distance,
> > wouldn't you just get one of them?
>
> Yeah, that is a hazard. I'm not sure whether <->'s results are
> sufficiently quantized to make that a big problem in practice.
It doesn't seem too far-fetched for trigram queries:
test=# select nm, nm <-> 'anders' from (values ('anderson'),('andersen'),('andersly')) x(nm); nm | ?column?
----------+----------anderson | 0.4andersen | 0.4andersly | 0.4
(3 rows)
test=# select distinct on (nm <-> 'anders') nm, nm <-> 'anders' from (values ('anderson'),('andersen'),('andersly'))
x(nm)order by nm <-> 'anders' limit 3; nm | ?column?
----------+----------anderson | 0.4
(1 row)
-Kevin
