$query = "SELECT guid, name, location, description, datetime FROM event";

   $result = doSQLTermError($db_connect, $query);

   while($obj = mysqli_fetch_object($result)){
      $guid = $obj->guid;

      $event_details = new stdClass;

      $event_details->$guid = new stdClass;
          $event_details->$guid->name = $obj->name;
          $event_details->$guid->location = $obj->location;
          $event_details->$guid->description = $obj->description;
          $event_details->$guid->datetime = $obj->datetime;
   }

   $event = json_encode($event_details);

"data":
{
   "f4ef863ef80b07036de08457ccdf51e3f814":
    {
       "name":"adsg",
       "location":"uhjty;",
       "description":"y;hy",
       "datetime":"2018-01-01 00:00:00"
    }
}