Upsert.php

<?php

namespace Drupal\Core\Database\Driver\sqlite;

use Drupal\Core\Database\Query\Upsert as QueryUpsert;

/**
 * SQLite implementation of \Drupal\Core\Database\Query\Upsert.
 */
class Upsert extends QueryUpsert {
    
    /**
     * {@inheritdoc}
     */
    public function __toString() {
        // Create a sanitized comment string to prepend to the query.
        $comments = $this->connection
            ->makeComment($this->comments);
        // Default fields are always placed first for consistency.
        $insert_fields = array_merge($this->defaultFields, $this->insertFields);
        $query = $comments . 'INSERT OR REPLACE INTO {' . $this->table . '} (' . implode(', ', $insert_fields) . ') VALUES ';
        $values = $this->getInsertPlaceholderFragment($this->insertValues, $this->defaultFields);
        $query .= implode(', ', $values);
        return $query;
    }

}