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Re: select unique items in db

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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.


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