A query is organized into terms and operators. There are two types of terms: Single Terms and Phrases.
A Single Term is a single word such as
test
or
hello
A Phrase is a group of words surrounded by double quotation marks such as
"hello dolly"
Multiple terms can be combined together with Boolean operators to form a more complex query (see below).
Lucene supports data in fields. When performing a search, you can either specify a field, or use the default field. The field names and default field are implementation-specific.
You can search any field by typing the field name followed by a colon ":" and then the term you are looking for.
As an example, let's assume a Lucene index contains two fields, title and contents, and contents is the default field. If you want to find the document titled "The Right Way" which contains the text "don't go this way", you can enter:
title:"The Right Way" AND contents:"don't go this way"
or
title:"The Right Way" AND "don't go this way"
Since contents is the default field, the field indicator is not required.
Note
The field is valid only for the term that it directly precedes, so the query
title:Do it right
will only find "Do" in the title field. It will find "it" and "right" in the default field (in this case the contents field).
Lucene supports modifying query terms to provide a wide range of searching options.
Wildcard Searches
Lucene supports single and multiple character wildcard searches.
To perform a single character wildcard search, use the "?" symbol.
To perform a multiple character wildcard search, use the "*" symbol.
The single character wildcard search looks for terms that match the query, with a single character replaced. For example, to search for "text" or "test", you can use:
te?t
Multiple character wildcard searches looks for 0 or more characters. For example, to search for test, tests or tester, you can use:
test*
You can also use wildcard searches in the middle of a term:
te*t
Note
You cannot use a * or ? symbol as the first character of a search.
Fuzzy Searches
Lucene supports fuzzy searches based on the Levenshtein Distance, or Edit Distance, algorithm. To invoke a fuzzy search, use the tilde, "~", symbol at the end of a Single-word Term. For example, to search for a term similar in spelling to "roam", use:
roam~
This search will find terms like foam and roams.
Proximity Searches
Lucene supports finding words that are within a specific distance. To do a proximity search, use the tilde, "~", symbol at the end of a Phrase. For example, to search for "apache" and "jakarta" within 10 words of each other in a document, use:
"jakarta apache"~10
Range Searches
Range Queries allow you to match documents whose field(s) values are between the lower and upper bound specified by the Range Query. Range Queries can be inclusive or exclusive of the upper and lower bounds. Sorting is lexicographic.
title:{Aida TO Carmen}
This will find all documents whose titles are between Aida and Carmen, but not including Aida and Carmen.
Inclusive range queries are denoted by square brackets. Exclusive range queries are denoted by curly brackets.
Boosting a Term
Lucene provides the relevance level of matching documents based on the terms found. To boost a term use the caret, "^", symbol with a boost factor (a number) at the end of the term you are searching. The higher the boost factor, the more relevant the term will be.
Boosting allows you to control the relevance of a document by boosting its term. For example, if you are searching for
jakarta apache
and you want the term "jakarta" to be more relevant, boost it by using the ^ symbol along with the boost factor next to the term. You would type:
jakarta^4 apache
This will make documents with the term jakarta appear more relevant. You can also boost Phrase Terms as in the example:
"jakarta apache"^4 "jakarta lucene"
By default, the boost factor is 1. Although the boost factor must be positive, it can be less than 1 (for example, 0.2)
Boolean operators allow terms to be combined through logic operators. Lucene supports OR, AND, "+", NOT and "-" as Boolean operators.
Note
Boolean operators must be ALL CAPS.
OR
The OR operator is the default conjunction operator. This means that if there is no Boolean operator between two terms, the OR operator is used. The OR operator links two terms and finds a matching document if either of the terms exist in a document. This is equivalent to a union using sets. The symbol || can be used in place of the word OR.
To search for documents that contain either "jakarta apache" or just "jakarta", use:
"jakarta apache" jakarta
or
"jakarta apache" OR jakarta
AND
The AND operator matches documents where both terms exist anywhere in the text of a single document. This is equivalent to an intersection using sets. The symbol && can be used in place of the word AND.
To search for documents that contain "jakarta apache" and "jakarta lucene", use:
"jakarta apache" AND "jakarta lucene"
+
The "+" or required operator requires that the term after the "+" symbol exists somewhere in a field of a single document.
To search for documents that must contain "jakarta" and may contain "lucene", use:
+jakarta lucene
NOT
The NOT operator excludes documents that contain the term after NOT. This is equivalent to a difference using sets. The symbol ! can be used in place of the word NOT.
To search for documents that contain "jakarta apache" but not "jakarta lucene", use:
"jakarta apache" NOT "jakarta lucene"
Note
The NOT operator cannot be used with just one term. For example, the following search will return no results:
NOT "jakarta apache"
-
The "-" or prohibit operator excludes documents that contain the term after the "-" symbol.
To search for documents that contain "jakarta apache" but not "jakarta lucene", use:
"jakarta apache" -"jakarta lucene"
Lucene supports using parentheses to group clauses to form sub queries. This can be very useful if you want to control the boolean logic for a query.
To search for either "jakarta" or "apache" and "website", use:
(jakarta OR apache) AND website
This eliminates any confusion and makes sure that website must exist and either term jakarta or apache may exist.
Lucene supports using parentheses to group multiple clauses to a single field.
To search for a title that contains both the word "return" and the phrase "pink panther", use:
title:(+return +"pink panther")
Lucene supports escaping special characters that are part of the query syntax. The current list of special characters are:
+ - && || ! ( ) { } [ ] ^ " ~ * ? : \
To escape these characters, use the \ before the character. For example to search for (1+1):2
, use:
\(1\+1\)\:2