Missing Aggregation

More info about missing aggregation is in the official elasticsearch docs

A field data based single bucket aggregation, that creates a bucket of all documents in the current document set context that are missing a field value.

Simple example

{
     "aggregations" : {
         "products_without_a_price" : {
             "missing" : { "field" : "price" }
         }
     }
 }

And now the query via DSL:

$missingAggregation = new MissingAggregation('products_without_a_price', 'price');

$search = new Search();
$search->addAggregation($missingAggregation);

$queryArray = $search->toArray();