Why are all these fields selected when I only want id

<?php
/**
 * @param string $parent_id
 * @param string $type
 * @param array $status
 * @param string $subject
 * @param bool $billing
 * @return bool|false|string
 */
function checkForTask(string $parent_id, $type = 'Order Master', $status = array(), $subject = '', $billing = false)
{
    try {
        $query = new SugarQuery();
        $from = $query->from(BeanFactory::newBean('Tasks'), IGNORE_TEAMS)->getFromAlias();
        $query->select(array("{$from}.id"));
        $query->where()->equals('task_type_c', $type);
        if ($billing) {
            $tasks = $query->join('tasks_tasks_1', IGNORE_TEAMS)->joinName();
            $query->where()->equals("{$tasks}.id", $parent_id);
        } else {
            $query->where()->equals('parent_id', $parent_id);
        }
        if (!empty($status)) {
            $query->where()->notIn('status', $status);
        }
        if (!empty($subject)) {
            $query->where()->equals('name', $subject);
        }

        $id = $query->getOne();
        if (empty($id)) {
            return false;
		} else {
			return $id;
		}
	}
	catch (SugarQueryException $e) {
		$GLOBALS['log']->fatal(print_r($e, true));
		return false;
	}
}