<spanclass="codefrag">docs/queryparsersyntax.html</span> that was distributed
with the version you are using.
</p>
<p>
Before choosing to use the provided Query Parser, please consider the following:
<ol>
<li>If you are programmatically generating a query string and then
parsing it with the query parser then you should seriously consider building
your queries directly with the query API. In other words, the query
parser is designed for human-entered text, not for program-generated
text.</li>
<li>Untokenized fields are best added directly to queries, and not
through the query parser. If a field's values are generated programmatically
by the application, then so should query clauses for this field.
An analyzer, which the query parser uses, is designed to convert human-entered
text to terms. Program-generated values, like dates, keywords, etc.,
should be consistently program-generated.</li>
<li>In a query form, fields which are general text should use the query
parser. All others, such as date ranges, keywords, etc. are better added
directly through the query API. A field with a limit set of values,
that can be specified with a pull-down menu should not be added to a
query string which is subsequently parsed, but rather added as a
TermQuery clause.</li>
</ol>
</p>
</div>
<aname="N10032"></a><aname="Terms"></a>
<h2class="boxed">Terms</h2>
<divclass="section">
<p>A query is broken up into terms and operators. There are two types of terms: Single Terms and Phrases.</p>
<p>A Single Term is a single word such as "test" or "hello".</p>
<p>A Phrase is a group of words surrounded by double quotes such as "hello dolly".</p>
<p>Multiple terms can be combined together with Boolean operators to form a more complex query (see below).</p>
<p>Note: The analyzer used to create the index will be used on the terms and phrases in the query string.
So it is important to choose an analyzer that will not interfere with the terms used in the query string.</p>
</div>
<aname="N10048"></a><aname="Fields"></a>
<h2class="boxed">Fields</h2>
<divclass="section">
<p>Lucene supports fielded data. When performing a search you can either specify a field, or use the default field. The field names and default field is implementation specific.</p>
<p>You can search any field by typing the field name followed by a colon ":" and then the term you are looking for. </p>
<p>As an example, let's assume a Lucene index contains two fields, title and text and text is the default field.
If you want to find the document entitled "The Right Way" which contains the text "don't go this way", you can enter: </p>
<preclass="code">title:"The Right Way" AND text:go</pre>
<p>or</p>
<preclass="code">title:"Do it right" AND right</pre>
<p>Since text is the default field, the field indicator is not required.</p>
<p>Note: The field is only valid for the term that it directly precedes, so the query</p>
<preclass="code">title:Do it right</pre>
<p>Will only find "Do" in the title field. It will find "it" and "right" in the default field (in this case the text field). </p>
</div>
<aname="N1006D"></a><aname="Term Modifiers"></a>
<h2class="boxed">Term Modifiers</h2>
<divclass="section">
<p>Lucene supports modifying query terms to provide a wide range of searching options.</p>
<p>To perform a single character wildcard search use the "?" symbol.</p>
<p>To perform a multiple character wildcard search use the "*" symbol.</p>
<p>The single character wildcard search looks for terms that match that with the single character replaced. For example, to search for "text" or "test" you can use the search:</p>
<preclass="code">te?t</pre>
<p>Multiple character wildcard searches looks for 0 or more characters. For example, to search for test, tests or tester, you can use the search: </p>
<preclass="code">test*</pre>
<p>You can also use the wildcard searches in the middle of a term.</p>
<preclass="code">te*t</pre>
<p>Note: You cannot use a * or ? symbol as the first character of a search.</p>
<aname="N1009B"></a><aname="Fuzzy Searches"></a>
<h3class="boxed">Fuzzy Searches</h3>
<p>Lucene supports fuzzy searches based on the Levenshtein Distance, or Edit Distance algorithm. To do 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 the fuzzy search: </p>
<preclass="code">roam~</pre>
<p>This search will find terms like foam and roams.</p>
<p>Starting with Lucene 1.9 an additional (optional) parameter can specify the required similarity. The value is between 0 and 1, with a value closer to 1 only terms with a higher similarity will be matched. For example:</p>
<preclass="code">roam~0.8</pre>
<p>The default that is used if the parameter is not given is 0.5.</p>
<p>Lucene supports finding words are a within a specific distance away. To do a proximity search use the tilde, "~", symbol at the end of a Phrase. For example to search for a "apache" and "jakarta" within 10 words of each other in a document use the search: </p>
<preclass="code">"jakarta apache"~10</pre>
<aname="N100C1"></a><aname="Range Searches"></a>
<h3class="boxed">Range Searches</h3>
<p>Range Queries allow one 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 done lexicographically.</p>
<preclass="code">mod_date:[20020101 TO 20030101]</pre>
<p>This will find documents whose mod_date fields have values between 20020101 and 20030101, inclusive.
Note that Range Queries are not reserved for date fields. You could also use range queries with non-date fields:</p>
<preclass="code">title:{Aida TO Carmen}</pre>
<p>This will find all documents whose titles are between Aida and Carmen, but not including Aida and Carmen.</p>
<p>Inclusive range queries are denoted by square brackets. Exclusive range queries are denoted by
curly brackets.</p>
<aname="N100DA"></a><aname="Boosting a Term"></a>
<h3class="boxed">Boosting a Term</h3>
<p>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.</p>
<p>Boosting allows you to control the relevance of a document by boosting its term. For example, if you are searching for</p>
<preclass="code">jakarta apache</pre>
<p>and you want the term "jakarta" to be more relevant boost it using the ^ symbol along with the boost factor next to the term.
You would type:</p>
<preclass="code">jakarta^4 apache</pre>
<p>This will make documents with the term jakarta appear more relevant. You can also boost Phrase Terms as in the example: </p>
<p>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.</p>
<p>To search for either "jakarta" or "apache" and "website" use the query:</p>
<preclass="code">(jakarta OR apache) AND website</pre>
<p>This eliminates any confusion and makes sure you that website must exist and either term jakarta or apache may exist.</p>
</div>
<aname="N10170"></a><aname="Field Grouping"></a>
<h2class="boxed">Field Grouping</h2>
<divclass="section">
<p>Lucene supports using parentheses to group multiple clauses to a single field.</p>
<p>To search for a title that contains both the word "return" and the phrase "pink panther" use the query:</p>
