yii\db\QueryBuilder::quoteTableNames PHP Method

    private function quoteTableNames($tables, &$params)
    {
        foreach ($tables as $i => $table) {
            if ($table instanceof Query) {
                list($sql, $params) = $this->build($table, $params);
                $tables[$i] = "({$sql}) " . $this->db->quoteTableName($i);
            } elseif (is_string($i)) {
                if (strpos($table, '(') === false) {
                    $table = $this->db->quoteTableName($table);
                }
                $tables[$i] = "{$table} " . $this->db->quoteTableName($i);
            } elseif (strpos($table, '(') === false) {
                if (preg_match('/^(.*?)(?i:\\s+as|)\\s+([^ ]+)$/', $table, $matches)) {
                    // with alias
                    $tables[$i] = $this->db->quoteTableName($matches[1]) . ' ' . $this->db->quoteTableName($matches[2]);
                } else {
                    $tables[$i] = $this->db->quoteTableName($table);
                }
            }
        }
        return $tables;
    }