'Execute the given SELECT statement and return results.
This method bypasses all internal statement compilation, and the
statement is executed without modification.
The statement argument is either a string, a ``select()`` construct,
or a ``text()`` construct, and should return the set of columns
appropriate to the entity class represented by this ``Query``.'

@_generative(_no_clauseelement_condition)
def from_statement(self, statement):

    if isinstance(statement, util.string_types):
        statement = sql.text(statement)
    if (not isinstance(statement, (expression.TextClause, expression.SelectBase))):
        raise sa_exc.ArgumentError('from_statement    accepts    text(),    select(),    and    union()    objects    only.')
    self._statement = statement
