Merge.php

<?php

namespace Drupal\mysql\Driver\Database\mysql;

use Drupal\Core\Database\Query\Merge as QueryMerge;

/**
 * MySQL implementation of \Drupal\Core\Database\Query\Merge.
 */
class Merge extends QueryMerge {
    
    /**
     * {@inheritdoc}
     */
    public function __construct(Connection $connection, string $table, array $options = []) {
        // @todo Remove the __construct in Drupal 11.
        // @see https://www.drupal.org/project/drupal/issues/3256524
        parent::__construct($connection, $table, $options);
        unset($this->queryOptions['return']);
    }

}