def exec_(self, columns=(), by=(), where=(), **kwds):
        """exec from self

        >>> t = q('([]a:1 2 3; b:10 20 30)')
        >>> t.exec_('a', where='b > 10').show()
        2 3
        """
        return self._seu('exec', columns, by, where, kwds)
exec from self

        >>> t = q('([]a:1 2 3; b:10 20 30)')
        >>> t.exec_('a', where='b > 10').show()
        2 3