Query Syntax

Query Syntax

Zulia's query parser is based on the lucene flexible query parser. The documentation here is slightly modified with some zulia specific tweaks and improvements.

Supported query syntax

A query consists of clauses, field specifications, grouping and Boolean operators and interval functions. We will discuss them in order.

Basic clauses

A query must contain one or more clauses. A clause can be a literal term, a phrase, a wildcard expression or other expression that

The following are some examples of simple one-clause queries:

• test
  • selects documents containing the word test (term clause).
• "test equipment"
  • phrase search; selects documents containing the phrase test equipment (phrase clause).
• "test failure"~4
  • proximity search; selects documents containing the words test and failure within 4 words (positions) from each other. The provided "proximity" is technically translated into "edit distance" (maximum number of atomic word-moving operations required to transform the document's phrase into the query phrase).
• tes*
  • prefix wildcard matching; selects documents containing words starting with tes, such as: test, testing or testable.
• /.est(s|ing)/
  • documents containing words matching the provided regular expression, such as resting or nests.
• nest~2
  • fuzzy term matching; documents containing words within 2-edits distance (2 additions, removals or replacements of a letter) from nest, such as test, net or rests.

Field specifications

Most clauses can be prefixed by a field name and a colon: the clause will then apply to that field only. If the field specification is omitted, the query parser will use the query fields given with the query. If fields are not given with the query, it will use the default search fields from the index config.

Note: in Zulia the fields from the original document can be indexed as different field name. The field name here refers to the indexed field name.

The following are some examples of field-prefixed clauses:

• title:test

  • documents containing test in the title field.

• title:(die OR hard)

  • documents containing die or hard in the title field.

• title,abstract:(die AND hard)

  • documents containing die AND hard in the title or abstract fields.

Boolean operators and grouping

You can combine clauses using Boolean AND, OR and NOT operators to form more complex expressions, for example:

• test AND results

  • selects documents containing both the word test and the word results.

• test OR suite OR results

  • selects documents with at least one of test, suite or results.

• title:test AND NOT title:complete

  • selects documents containing test and not containing complete in the title field.

• title:test AND (pass* OR fail*)

  • grouping; use parentheses to specify the precedence of terms in a Boolean clause. Query will match documents containing test in the title field and a word starting with pass or fail in the default search fields.

• title:(pass fail skip)

  • if the default operator for the query is OR (default), documents containing any of pass, fail or skip in the title field.
  • if the default operator for the query is AND, documents containing all of pass, fail or skip in the title field.

• title:(+test +"result unknown")

  • + indicates or phrase is required
  • if the default operator for the query is OR (default), documents containing both test and result in the title field. The unknown term will be used for scoring
  • if the default operator for the query is AND, the + for required does not change the query and gives documents containing both test, result, and unknown in the title field.

Note the Boolean operators must be written in all caps, otherwise they are parsed as regular terms.

Range operators

To search for ranges of textual or numeric values, use square or curly brackets, for example:

• name:[Jones TO Smith]

  • inclusive range; selects documents whose name field has any value between Jones and Smith, including boundaries.

• score:{2.5 TO 7.3}

  • exclusive range; selects documents whose score field is between 2.5 and 7.3, excluding boundaries.

• score:{2.5 TO *] *one-sided range; selects documents whose score field is larger than 2.5.

Term boosting

Terms, quoted terms, term range expressions and grouped clauses can have a floating-point weight boost applied to them to increase their score relative to other clauses. For example:

• jones^2 OR smith^0.5

  • prioritize documents with jones term over matches on the smith term.

• field:(a OR b NOT c)^2.5 OR field:d

  • apply the boost to a sub-query.

Minimum-should-match constraint for Boolean disjunction groups

A minimum-should-match operator can be applied to a disjunction Boolean query (a query with only "OR"-subclauses) and forces the query to match documents with at least the provided number of these subclauses. For example:

• (blue crab fish)@2

  • matches all documents with at least two terms from the set [blue, crab, fish] (in any order).
  • also can be written as (blue crab fish)~2

• ((yellow OR blue) crab fish)@2

  • sub-clauses of a Boolean query can themselves be complex queries; here the min-should-match selects documents that match at least two of the provided three sub-clauses.
  • also can be written as ((yellow OR blue) crab fish)~2

Interval function clauses

Interval functions are a powerful tool to express search needs in terms of one or more * contiguous fragments of text and their relationship to one another. All interval clauses start with the fn: prefix (possibly prefixed by a field specification). For example:

• fn:ordered(quick brown fox)

  • matches all documents (in the default field or in multi-field expansion) with at least one ordered sequence of quick, brown and fox terms.

• title,abstract:fn:maxwidth(5 fn:atLeast(2 quick brown fox))

  • matches all documents in the title or abstract field where at least two of the three terms (quick, brown and fox) occur within five positions of each other.