Обсуждение: Rank based on the number of matching OR fields?
I want to run a query like to_tsquery("A | B | C") and then rank the
results so that if a document contained A, B, and C, then it would
rank above a document that just had some subset.
How would I do such a thing?
--
W. Matthew Wilson
matt@tplus1.com
http://tplus1.com
Le 2012-09-25 à 14:16, W. Matthew Wilson a écrit :
I want to run a query like to_tsquery("A | B | C") and then rank the
results so that if a document contained A, B, and C, then it would
rank above a document that just had some subset.
How would I do such a thing?
Hope that helps,
François Beausoleil
If you're easily able to do it, (i.e. you're building rather than receiving the query), you could rank them by the conjunction of the search terms first:
ORDER BY ts_rank(vector, to_tsquery('A & B & C')) desc, ts_rank(vector, to_tsquery('A | B | C')) desc
Or just explicitly order by whether the conjunction matches:
ORDER BY case when to_tsquery('A & B & C') @@ vector then 0 else 1 end, ts_rank(vector, to_tsquery('A | B | C')) desc
I think either of these would have the property you want, but I don't know how they would otherwise affect the quality of the ranking. You should set up a test group of documents and make sure your mechanism ranks that group properly on test queries.
Joel
On Tue, Sep 25, 2012 at 11:16 AM, W. Matthew Wilson <matt@tplus1.com> wrote:
I want to run a query like to_tsquery("A | B | C") and then rank the
results so that if a document contained A, B, and C, then it would
rank above a document that just had some subset.
How would I do such a thing?
--
W. Matthew Wilson
matt@tplus1.com
http://tplus1.com
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