Extended Stats Aggregation

More info about extended stats aggregation is in the official elasticsearch docs

A multi-value metrics aggregation that computes stats over numeric values extracted from the aggregated documents.

Simple example

{
    "aggregations" : {
        "grades_stats" : {
            "extended_stats" : { "field" : "grade" }
        }
    }
}

And now the query via DSL:

$extendedStatsAggregation = new ExtendedStatsAggregation('grades_stats', 'grade');

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

$queryArray = $search->toArray();