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. Optional. Default is true (case insensitive). |
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 | Boosts the query by the given multiplier. Useful for searches that contain more than one query. Values in the [0, 1) range decrease relevance, and values greater than 1 increase relevance. Default is 1. |
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, wildcard queries are not run.