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Exists Filter
editExists Filter
editReturns documents that have at least one non-null
value in the original field:
{ "constant_score" : { "filter" : { "exists" : { "field" : "user" } } } }
For instance, these documents would all match the above filter:
An empty string is a non- |
|
Even though the |
|
At least one non- |
These documents would not match the above filter:
This field has no values. |
|
At least one non- |
|
The |
null_value
mapping
editIf the field mapping includes the null_value
setting (see Core Types)
then explicit null
values are replaced with the specified null_value
. For
instance, if the user
field were mapped as follows:
"user": { "type": "string", "null_value": "_null_" }
then explicit null
values would be indexed as the string _null_
, and the
following docs would match the exists
filter:
{ "user": null } { "user": [null] }
However, these docs—without explicit null
values—would still have
no values in the user
field and thus would not match the exists
filter:
{ "user": [] } { "foo": "bar" }
Caching
editThe result of the filter is always cached.