ORM::raw_join PHP Method

    public function raw_join($table, $constraint, $table_alias, $parameters = array())
    {
        // Add table alias if present
        if (!is_null($table_alias)) {
            $table_alias = $this->_quote_identifier($table_alias);
            $table .= " {$table_alias}";
        }
        $this->_values = array_merge($this->_values, $parameters);
        // Build the constraint
        if (is_array($constraint)) {
            list($first_column, $operator, $second_column) = $constraint;
            $first_column = $this->_quote_identifier($first_column);
            $second_column = $this->_quote_identifier($second_column);
            $constraint = "{$first_column} {$operator} {$second_column}";
        }
        $this->_join_sources[] = "{$table} ON {$constraint}";
        return $this;
    }