opensearch-docs-cn/_query-dsl/term/wildcard.md

---
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.
`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:

```json
GET shakespeare/_search
{
  "query": {
    "wildcard": {
      "speaker": {
        "value": "H*Y",
	"case_insensitive": false
      }
    }
  }
}
```
{% 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}