Thanks Chris, this is useful, we can you the query format you suggest, Karen
On Tuesday 15 January 2008 01:13:14 Chris Hostetter wrote: > Several things in this thread should be clarified (note: order of > quotations munged for clarity)... > > : I had read this page. But I'm not using the "NOT" operator, I'm using > : the "-" operator. I'm assuming there is a subtle difference between them > : in that NOT qualifies something else, hence needs 2 terms. Isn't the "-" > : operator supposed to be a complement to the "+" operator, ie. excludes > : something rather than requiring it ? > > "The NOT operator" and "the - operator" are in fact the same thing ... the > duplicate syntax comes from Lucene trying to appease people that > want boolean style operator synta (AND/OR/NOT) even though the query > parser is not a boolean syntax. > > : > Have you seen this page? > : > http://lucene.apache.org/java/docs/queryparsersyntax.html > : > > : > From that page: > : > Note: The NOT operator cannot be used with just one term. For example, > : > the following search will return no results: > : > NOT "jakarta apache" > > In Solr, the query parser can in fact support purely negative queries, by > internally transforming the query, this is noted on the Solr query syntax > wiki... > > http://wiki.apache.org/solr/SolrQuerySyntax > > : > > field_name:(-null) > > "null" is not a special keyword, if you look at the debugging output when > doing that query you'll see that it is the same as: -field_name:null > ... which is a search for all docs containing the string "null" in the > field "field_name". > > : The *:* (star colon star) means "all records". The trick is to use (*:* > : AND -field:[* TO *]). It's silly, but there it is. > > as i mentioned, you can do pure wildcard queries now, so a simple search > for -field_name:[* TO *] will find all docs that have no indexed values > for that field at all. > > : A performance note: we switched from empty fields to fields with a > : standard 'empty' value. This way we don't have to do a range check to > : find records with empty fields. > > Your milage may vary depending on how many docs you have with "no value" > ... this also issn't practical when dealing with numeric, boolean, or date > based fields. (and depending on how much churn there is in your index, > the filterCache can probably make the difference negliable on average > anyway). > > > > > -Hoss
