@classmethod
def join_table(cls, second_table, first_table, lhs_on, rhs_on='id'):
    """
        Builds the fragment for joined tables, e.g.
        'join second_table as t2 on t1.lhs_on = t2.rhs_on'
        """
    args = first_table.alias, lhs_on, second_table.alias, rhs_on
    identifiers = cls.identifiers(args)
    sql = 'join {} on {}.{} = {}.{}'
    return cls.format(sql, cls.table_name(second_table), *identifiers)
