for drawks

sqlalchemy translation.py

# http://stackoverflow.com/questions/16172084/postgresql-join-only-most-specific-cidr-match/16172369#16172369
subselect = sa.select([
        test_systems.c.address.label('hostaddr'),
        test_networks.c.address.label('netaddr'),
        test_networks.c.description.label('description'),
        sa.func.row_number().over(partition_by=test_systems.c.address, order_by=sa.func.masklen(test_networks.c.address).desc()).label('row')
    ], from_obj=test_systems.outerjoin(test_networks, test_systems.c.address.op('<<')(test_networks.c.address))).alias('x')

query = sa.select([
        x.c.hostaddr,
        x.c.netaddr,
        x.c.description
    ]).where(x.c.row == 1)