php - How can I access private property of BigQueryTimestamp

Solution:

I recommend asking for rawResults that don't turn timestamps into objects, as that is counter productive.

 $queryResults = $bigQuery->runQuery($jobConfig, array(
            'timeoutMs' => 55 * 10000,
            'returnRawResults' => true
        ));

This way each entry is returned as a simple plain value.

Solution:

As suggested by iainn in the comment, using the get method of the class works perfectly.

$dateTime = $row["created_at"]->get()->format('d-m-Y H:i:s');