'Called when building a ``SELECT`` statement, position is just
before column list Firebird puts the limit and offset right
after the ``SELECT``...'

def get_select_precolumns(self, select):

    result = ''
    if select._limit:
        result += ('FIRST    %s    ' % self.process(sql.literal(select._limit)))
    if select._offset:
        result += ('SKIP    %s    ' % self.process(sql.literal(select._offset)))
    if select._distinct:
        result += 'DISTINCT    '
    return result
