67 lines
2.2 KiB
Markdown
67 lines
2.2 KiB
Markdown
|
---
|
||
|
|
layout: default
|
||
|
|
title: Wildcard
|
||
|
|
parent: Term-level queries
|
||
|
|
grand_parent: Query DSL
|
||
|
|
nav_order: 100
|
||
|
|
---
|
||
|
|
|
||
|
|
# 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.
|
||
|
|
|
||
|
|
To search for terms that start with `H` and end with `Y`, use the following request:
|
||
|
|
|
||
|
|
```json
|
||
|
|
GET shakespeare/_search
|
||
|
|
{
|
||
|
|
"query": {
|
||
|
|
"wildcard": {
|
||
|
|
"speaker": {
|
||
|
|
"value": "H*Y"
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
{% include copy-curl.html %}
|
||
|
|
|
||
|
|
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:
|
||
|
|
|
||
|
|
```json
|
||
|
|
GET _search
|
||
|
|
{
|
||
|
|
"query": {
|
||
|
|
"wildcard": {
|
||
|
|
"<field>": {
|
||
|
|
"value": "patt*rn",
|
||
|
|
...
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
```
|
||
|
|
{% include copy-curl.html %}
|
||
|
|
|
||
|
|
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`]({{site.url}}{{site.baseurl}}/query-dsl/index/#expensive-queries) is set to `false`, wildcard queries are not run.
|
||
|
|
{: .important}
|