[[kuery-query]]
=== {kib} Query Language

The {kib} Query Language (KQL) is a simple text-based query language for filtering data.

* KQL only filters data, and has no role in aggregating, transforming, or sorting data.
* KQL is not to be confused with the <<lucene-query,Lucene query language>>, which has a different feature set.

Use KQL to filter documents where a value for a field exists, matches a given value, or is within a given range.

[discrete]
=== Filter for documents where a field exists

To filter documents for which an indexed value exists for a given field, use the `*` operator.
For example, to filter for documents where the `http.request.method` field exists, use the following syntax:

[source,yaml]
-------------------
http.request.method: *
-------------------

This checks for any indexed value, including an empty string.

[discrete]
=== Filter for documents that match  a value

Use KQL to filter for documents that match a specific number, text, date, or boolean value.
For example, to filter for documents where the `http.request.method` is GET, use the following query:

[source,yaml]
-------------------
http.request.method: GET
-------------------

The field parameter is optional. If not provided, all fields are searched for the given value.
For example, to search all fields for “Hello”, use the following:

[source,yaml]
-------------------
Hello
-------------------

When querying keyword, numeric, date, or boolean fields, the value must be an exact match,
including punctuation and case. However, when querying text fields, {es} analyzes the
value provided according to the {ref}/analysis.html[field’s mapping settings].
For example, to search for documents where `http.request.body.content` (a `text` field)
contains the text “null pointer”:

[source,yaml]
-------------------
http.request.body.content: null pointer
-------------------

Because this is a `text` field, the order of these search terms does not matter, and
even documents containing “pointer null” are returned. To search `text` fields where the
terms are in the order provided, surround the value in quotation marks, as follows:

[source,yaml]
-------------------
http.request.body.content: "null pointer"
-------------------

Certain characters must be escaped by a backslash (unless surrounded by quotes).
For example, to search for documents where `http.request.referrer` is https://example.com,
use either of the following queries:

[source,yaml]
-------------------
http.request.referrer: "https://example.com"
http.request.referrer: https\://example.com
-------------------

You must escape following characters:

[source,yaml]
-------------------
\():<>"*
-------------------

[discrete]
=== Filter for documents within a range

To search documents that contain terms within a provided range, use KQL’s range syntax.
For example, to search for all documents for which `http.response.bytes` is less than 10000,
use the following syntax:

[source,yaml]
-------------------
http.response.bytes < 10000
-------------------

To search for an inclusive range, combine multiple range queries.
For example, to search for documents where `http.response.bytes` is greater than 10000
but less than or equal to 20000, use the following syntax:

[source,yaml]
-------------------
http.response.bytes > 10000 and http.response.bytes <= 20000
-------------------

You can also use range syntax for string values, IP addresses, and timestamps.
For example, to search for documents earlier than two weeks ago, use the following syntax:

[source,yaml]
-------------------
@timestamp < now-2w
-------------------

For more examples on acceptable date formats, refer to {ref}/common-options.html#date-math[Date Math].

[discrete]
=== Filter for documents using wildcards

To search for documents matching a pattern, use the wildcard syntax.
For example, to find documents where `http.response.status_code` begins with a 4, use the following syntax:

[source,yaml]
-------------------
http.response.status_code: 4*
-------------------

By default, leading wildcards are not allowed for performance reasons.
You can modify this with the <<query-allowleadingwildcards,`query:allowLeadingWildcards`>> advanced setting.

NOTE: Only `*` is currently supported. This matches zero or more characters.

[discrete]
=== Negating a query

To negate or exclude a set of documents, use the `not` keyword (not case-sensitive).
For example, to filter documents where the `http.request.method` is *not* GET, use the following query:

[source,yaml]
-------------------
NOT http.request.method: GET
-------------------

[discrete]
=== Combining multiple queries

To combine multiple queries, use the `and`/`or` keywords (not case-sensitive).
For example, to find documents where the `http.request.method` is GET *or* the `http.response.status_code` is 400,
use the following query:

[source,yaml]
-------------------
http.request.method: GET OR http.response.status_code: 400
-------------------

Similarly, to find documents where the `http.request.method` is GET *and* the
`http.response.status_code` is 400, use this query:

[source,yaml]
-------------------
http.request.method: GET AND http.response.status_code: 400
-------------------

To specify precedence when combining multiple queries, use parentheses.
For example, to find documents where the `http.request.method` is GET *and*
the `http.response.status_code` is 200, *or* the `http.request.method` is POST *and*
`http.response.status_code` is 400, use the following:

[source,yaml]
-------------------
(http.request.method: GET AND http.response.status_code: 200) OR
(http.request.method: POST AND http.response.status_code: 400)
-------------------

You can also use parentheses for shorthand syntax when querying multiple values for the same field.
For example, to find documents where the `http.request.method` is GET, POST, *or* DELETE, use the following:

[source,yaml]
-------------------
http.request.method: (GET OR POST OR DELETE)
-------------------

[discrete]
=== Matching multiple fields

Wildcards can also be used to query multiple fields. For example, to search for
documents where any sub-field of `datastream` contains “logs”, use the following:

[source,yaml]
-------------------
datastream.*: logs
-------------------

NOTE: When using wildcards to query multiple fields, errors might occur if the fields are of
different types. For example, if `datastream.*` matches both numeric and string fields, the
above query will result in an error because numeric fields cannot be queried for string values.

[discrete]
=== Querying nested fields

Querying {ref}/nested.html[nested fields] requires a special syntax. Consider the
following document, where `user` is a nested field:

[source,yaml]
-------------------
{
  "user" : [
    {
      "first" : "John",
      "last" :  "Smith"
    },
    {
      "first" : "Alice",
      "last" :  "White"
    }
  ]
}
-------------------

To find documents where a single value inside the `user` array contains a first name of
“Alice” and last name of “White”, use the following:

[source,yaml]
-------------------
user:{ first: "Alice" and last: "White" }
-------------------

Because nested fields can be inside other nested fields,
you must specify the full path of the nested field you want to query.
For example, consider the following document where `user` and `names` are both nested fields:

[source,yaml]
-------------------
{
  "user": [
    {
      "names": [
        {
          "first": "John",
          "last": "Smith"
        },
        {
          "first": "Alice",
          "last": "White"
        }
      ]
    }
  ]
}
-------------------

To find documents where a single value inside the `user.names` array contains a first name of “Alice” *and*
last name of “White”, use the following:

[source,yaml]
-------------------
user.names:{ first: "Alice" and last: "White" }
-------------------
