I found something kind fo weird about the way lucene interprets boolean
expressions wihout parenthesis.
when i run the query A AND B OR C, it returns only the documents that have A(in
other words as if the query was just the term A).
when I run the query A OR B AND C, it returns only the documents that have B
AND C(as if teh query was just B AND C ). I set the default operator in my
application to be AND.
can anyone explain this behavior, thanks.
-Original Message-
From: Morus Walter [mailto:[EMAIL PROTECTED]
Sent: Monday, February 28, 2005 2:40 AM
To: Lucene Users List
Subject: Re: help with boolean expression
Omar Didi writes:
> I have a problem understanding how would lucene iterpret this boolean
> expression : A AND B OR C .
> it neither return the same count as when I enter (A AND B) OR C nor A AND (B
> OR C).
> if anyone knows how it is interpreted i would be thankful.
> thanks
A AND B OR C creates a query that requires A and B. C influcenes the
score, but is neither sufficient nor required for a match.
IMO query parser is broken for queries mixing AND and OR without explicit
braces.
My favorite sample is `a AND b OR c AND d' which equals `a AND b AND c AND d'
in query parser.
I suggested a patch some time ago, but it's still pending in bugzilla.
http://issues.apache.org/bugzilla/show_bug.cgi?id=25820
Don't know if it's still usable with current sources.
Morus
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