筛选/限制Django order_by [英] filter/limit django order_by

问题描述

使用django ORM，有没有办法限制或过滤order_by适用的范围？

Using the django ORM, Is there a way to limit or filter the scope of what order_by applies to?

Product.objects.filter(
    product_type__name=choices.PRODUCT_BOOK
).order_by(
    # need to order these last names by those 
    # who have a role code of "A01", then "B01"
    'contributor__writer__last_name'
)

推荐答案

即使使用原始SQL，也无法仅对某些行应用订单。因此，最好的方法是将alls排序并按role_code分组。

Even using raw SQL is not possible to apply an order by just to some rows. So the best way, order alls and group by role_code.

您还可以使用 role_code A01 或 B01 ，对其进行订购，然后获取其余贡献者（如果 role_code ） > A01 或 B01 。然后合并查询结果。

Also you can get contributors with role_code "A01" or "B01", order them, then get the rest contributors excluding their role_code if is "A01" or "B01". Then merge query results.

order_products = Product.objects.filter(
    product_type__name=choices.PRODUCT_BOOK
).filter(contributor__role_code__in=['A01','B01'])
.order_by(
    # need to order these last names by those 
    # who have a role code of "A01", then "B01"
    'contributor__writer__last_name'
)

non_order_products = Product.objects.filter(
    product_type__name=choices.PRODUCT_BOOK
).exclude(contributor__role_code__in=['A01','B01'])

final_result = order_products | non_order_products

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