Exists query
Use the exists
query to search for documents that contain a specific field.
An indexed value will not exist for a document field in any of the following cases:
- The field has
"index" : false
specified in the mapping. - The field in the source JSON is
null
or[]
. - The length of the field value exceeds the
ignore_above
setting in the mapping. - The field value is malformed and
ignore_malformed
is defined in the mapping.
An indexed value will exist for a document field in any of the following cases:
- The value is an array that contains one or more null elements and one or more non-null elements (for example,
["one", null]
). - The value is an empty string (
""
or"-"
). - The value is a custom
null_value
, as defined in the field mapping.
Example
For example, consider an index that contains the following two documents:
PUT testindex/_doc/1
{
"title": "The wind rises"
}
PUT testindex/_doc/2
{
"title": "Gone with the wind",
"description": "A 1939 American epic historical film"
}
The following query searches for documents that contain the description
field:
GET testindex/_search
{
"query": {
"exists": {
"field": "description"
}
}
}
The response contains the matching document:
{
"took": 3,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 1,
"hits": [
{
"_index": "testindex",
"_id": "2",
"_score": 1,
"_source": {
"title": "Gone with the wind",
"description": "A 1939 American epic historical film"
}
}
]
}
}
Finding documents with missing indexed values
To find documents with missing indexed values, you can use the must_not
Boolean query with the inner exists
query. For example, the following request searches for documents in which the description
field is missing:
GET testindex/_search
{
"query": {
"bool": {
"must_not": {
"exists": {
"field": "description"
}
}
}
}
}
The response contains the matching document:
{
"took": 19,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 0,
"hits": [
{
"_index": "testindex",
"_id": "1",
"_score": 0,
"_source": {
"title": "The wind rises"
}
}
]
}
}
Parameters
The query accepts the name of the field (<field>
) as a top-level parameter.