opensearch-docs-cn/_search-plugins/sql/sql/functions.md

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default	Functions	SQL	SQL and PPL	7	/search-plugins/sql/functions/

Functions

The SQL language supports all SQL plugin common functions, including relevance search, but also introduces a few function synonyms, which are available in SQL only. These synonyms are provided by the V1 engine. For more information, see Limitations.

Match query

The MATCHQUERY and MATCH_QUERY functions are synonyms for the MATCH relevance function. They don't accept additional arguments but provide an alternate syntax.

Syntax

To use matchquery or match_query, pass in your search query and the field name that you want to search against:

match_query(field_expression, query_expression[, option=<option_value>]*)
matchquery(field_expression, query_expression[, option=<option_value>]*)
field_expression = match_query(query_expression[, option=<option_value>]*)
field_expression = matchquery(query_expression[, option=<option_value>]*)

You can specify the following options in any order:

• analyzer
• boost

Example

You can use MATCHQUERY to replace MATCH:

SELECT account_number, address
FROM accounts
WHERE MATCHQUERY(address, 'Holmes')

Alternatively, you can use MATCH_QUERY to replace MATCH:

SELECT account_number, address
FROM accounts
WHERE address = MATCH_QUERY('Holmes')

The results contain documents in which the address contains "Holmes":

account_number	address
1	880 Holmes Lane

Multi-match

There are three synonyms for MULTI_MATCH, each with a slightly different syntax. They accept a query string and a fields list with weights. They can also accept additional optional parameters.

Syntax

multimatch('query'=query_expression[, 'fields'=field_expression][, option=<option_value>]*)
multi_match('query'=query_expression[, 'fields'=field_expression][, option=<option_value>]*)
multimatchquery('query'=query_expression[, 'fields'=field_expression][, option=<option_value>]*)

The fields parameter is optional and can contain a single field or a comma-separated list (whitespace characters are not allowed). The weight for each field is optional and is specified after the field name. It should be delimited by the caret character -- ^ -- without whitespace.

Example

The following queries show the fields parameter of a multi-match query with a single field and a field list:

multi_match('fields' = "Tags^2,Title^3.4,Body,Comments^0.3", ...)
multi_match('fields' = "Title", ...)

You can specify the following options in any order:

• analyzer
• boost
• slop
• type
• tie_breaker
• operator

Query string

The QUERY function is a synonym for QUERY_STRING.

Syntax

query('query'=query_expression[, 'fields'=field_expression][, option=<option_value>]*)

The fields parameter is optional and can contain a single field or a comma-separated list (whitespace characters are not allowed). The weight for each field is optional and is specified after the field name. It should be delimited by the caret character -- ^ -- without whitespace.

Example

The following queries show the fields parameter of a multi-match query with a single field and a field list:

query('fields' = "Tags^2,Title^3.4,Body,Comments^0.3", ...)
query('fields' = "Tags", ...)

You can specify the following options in any order:

• analyzer
• boost
• slop
• default_field

Example of using query_string in SQL and PPL queries:

The following is a sample REST API search request in OpenSearch DSL.

GET accounts/_search
{
  "query": {
    "query_string": {
      "query": "Lane Street",
      "fields": [ "address" ],
    }
  }
}

The request above is equivalent to the following query function:

SELECT account_number, address
FROM accounts
WHERE query('address:Lane OR address:Street')

The results contain addresses that contain "Lane" or "Street":

account_number	address
1	880 Holmes Lane
6	671 Bristol Street
13	789 Madison Street

Match phrase

The MATCHPHRASEQUERY function is a synonym for MATCH_PHRASE.

Syntax

matchphrasequery(query_expression, field_expression[, option=<option_value>]*)

You can specify the following options in any order:

• analyzer
• boost
• slop

Score query

To return a relevance score along with every matching document, use the SCORE, SCOREQUERY, or SCORE_QUERY functions.

Syntax

The SCORE function expects two arguments. The first argument is the MATCH_QUERY expression. The second argument is an optional floating-point number to boost the score (the default value is 1.0):

SCORE(match_query_expression, score)
SCOREQUERY(match_query_expression, score)
SCORE_QUERY(match_query_expression, score)

Example

The following example uses the SCORE function to boost the documents' scores:

SELECT account_number, address, _score
FROM accounts
WHERE SCORE(MATCH_QUERY(address, 'Lane'), 0.5) OR
  SCORE(MATCH_QUERY(address, 'Street'), 100)
ORDER BY _score

The results contain matches with corresponding scores:

account_number	address	score
1	880 Holmes Lane	0.5
6	671 Bristol Street	100
13	789 Madison Street	100

Wildcard query

To search documents by a given wildcard, use the WILDCARDQUERY or WILDCARD_QUERY functions.

Syntax

wildcardquery(field_expression, query_expression[, boost=<value>])
wildcard_query(field_expression, query_expression[, boost=<value>])

Example

The following example uses a wildcard query:

SELECT account_number, address
FROM accounts
WHERE wildcard_query(address, '*Holmes*');

The results contain documents that match the wildcard expression:

account_number	address
1	880 Holmes Lane