On Tue, Dec 09, 2003 at 10:57:51AM +0100, Morus Walter wrote: > Hi, > > I'm having problems understanding query parsers handling of AND and OR > if there's more than one operator. > > E.g. > a OR b AND c > gives the same number of hits as > b AND c > (only scores are different)
This would make sense if all the document that have a also have both B and C in them. > > and > a AND b OR c AND d > seems to be equivalent to > a AND b AND C AND d > That's not what I get. http://www.fastbuzz.com/search/results.jsp?query=dean+AND+kerry+AND+clark+AND+gephardt&days= returns 479 items but http://www.fastbuzz.com/search/results.jsp?query=dean+AND+kerry+OR+clark+AND+gephardt&days= returns 564 items which indicates that the OR does make a difference. As expcted, you end up getting more items with the OR. Regards, Dror > which doesn't seem logical to me. > > I'd expect to have AND higher precedence than OR (as a logical AND / OR in > C or Java) so that a OR b AND c would be equivalent to a OR (b AND c) > and a AND b OR c AND d equivalent to (a AND b) OR (c AND d) > > > When I look at the query parsers sources, I find, that -- unless paranthesis > are used -- all these terms are added to one boolean query, and the > AND operator makes the term left and right of it required (unless there > are NOT operators making them prohibited). > So > a OR b AND c gives one boolean query where b and c are required, whereas > a is not. > a AND b OR c AND d produces a boolean query where a, b, c and d are required, > which is indeed the same as a AND b AND c AND d. > > > Should this be considered a bug? > > greetings > Morus > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > -- Dror Matalon Zapatec Inc 1700 MLK Way Berkeley, CA 94709 http://www.fastbuzz.com http://www.zapatec.com --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
