Re: select unique items in db

a schreef:
> this doesnt work
>
> SELECT DISTINCT on link *, rank(ts_vec, to_tsquery('default', $qtxt))
> FROM feed_entry WHE RE ts_vec @@ to_tsquery('default', $qtxt) ORDER
> BY rank(ts_vec, to_tsquery('default', $qtxt)) DESC LIMIT 5 OFFSET 0
>
> can you tell me how to get the DISTINCT elements in LINK
> thanks

Just place your distinct fields between ().

example syntax:
SELECT DISTINCT ON (field1, field2, fieldn) field1, field4
in your case:
SELECT DISTINCT ON (link) *, rank[...]

Do remember that if you select different fields than the ones you use in
the distinct, the results may not always be what you want.

e.g.:

suppose you have this data loaded in the a table:

id field1 field2
-- ------ ------
1 foo fooble
2 bar barble
3 foo wobble
4 woo wibble
5 foo bobble

if you "select distinct on (field1) *" which of the records with foo in
field1 is going to be returned 1, 3 or 5? I believe this doesn't
nescescarily has to be the same value each time.