from sqlalchemy import *
from sqlalchemy.sql import _Grouping

db = create_engine('sqlite://')
md = BoundMetaData(db.engine)

foo = Table('foo',md,Column('id',Integer,primary_key=True))
foo.create()

for i in range(1,20):
    foo.insert().execute(id=i)

md.engine.echo=True
print list(except_(
        select([foo.c.id], foo.c.id.op('%')(2) == 0),
        _Grouping(except_(
            select([foo.c.id], foo.c.id.op('%')(3) == 0),
            select([foo.c.id], foo.c.id.op('%')(4) == 0)
        ))).execute())
# Expecting 2, 4, 8, 10, 12, 14, 16 - not 2, 10, 14