Comment by amalashkevich

There is no need to wrap it with a query. You can just add a filter:

    mynewquery = myquery.filter(lambda c: c.name > 'G')

The new query will produce the following SQL:

    SELECT `c`.`id`
    FROM `customer` `c`
      LEFT JOIN `order` `order-1`
        ON `c`.`id` = `order-1`.`customer`
    WHERE `c`.`name` > 'G'
    GROUP BY `c`.`id`
    HAVING coalesce(SUM(`order-1`.`total_price`), 0) > 1000