Wildcard query
Use wildcard queries to search for terms that match a wildcard pattern. Wildcard queries support the following operators.
| Operator | Description |
|---|---|
* | Matches zero or more characters. |
? | Matches any single character. |
case_insensitive | If true, the wildcard query is case insensitive. If false, the wildcard query is case sensitive. Default is false (case sensitive). |
For a case-sensitive search for terms that start with H and end with Y, use the following request:
GET shakespeare/_search
{
"query": {
"wildcard": {
"speaker": {
"value": "H*Y",
"case_insensitive": false
}
}
}
}
If you change * to ?, you get no matches because ? refers to a single character.
Wildcard queries tend to be slow because they need to iterate over a lot of terms. Avoid placing wildcard characters at the beginning of a query because it could be a very expensive operation in terms of both resources and time.
Parameters
The query accepts the name of the field (<field>) as a top-level parameter:
GET _search
{
"query": {
"wildcard": {
"<field>": {
"value": "patt*rn",
...
}
}
}
}
The <field> accepts the following parameters. All parameters except value are optional.
| Parameter | Data type | Description |
|---|---|---|
value | String | The wildcard pattern used for matching terms in the field specified in <field>. |
boost | Floating-point | A floating-point value that specifies the weight of this field toward the relevance score. Values above 1.0 increase the field’s relevance. Values between 0.0 and 1.0 decrease the field’s relevance. Default is 1.0. |
case_insensitive | Boolean | If true, allows case-insensitive matching of the value with the indexed field values. Default is false (case sensitivity is determined by the field’s mapping). |
rewrite | String | Determines how OpenSearch rewrites and scores multi-term queries. Valid values are constant_score, scoring_boolean, constant_score_boolean, top_terms_N, top_terms_boost_N, and top_terms_blended_freqs_N. Default is constant_score. |
If search.allow_expensive_queries is set to false, then wildcard queries are not executed.