python - 将 AND 和 OR 与 Q 对象组合的 Django 查询过滤器不返回预期结果

Question

我尝试使用 Q 对象在过滤器中组合 AND 和 OR。看起来 |表现得像一个 AND。这与之前在同一查询中运行的注释有关，而不是作为子查询。

用 Django 处理这个问题的正确方法是什么？

models.py

class Type(models.Model):
    name = models.CharField(_('name'), max_length=100)
    stock = models.BooleanField(_('in stock'), default=True)
    hide = models.BooleanField(_('hide'), default=False)
    deleted = models.BooleanField(_('deleted'), default=False)

class Item(models.Model):
    barcode = models.CharField(_('barcode'), max_length=100, blank=True)
    quantity = models.IntegerField(_('quantity'), default=1)
    type = models.ForeignKey('Type', related_name='items', verbose_name=_('type'))

views.py

def hire(request):
    categories_list = Category.objects.all().order_by('sorting')
    types_list = Type.objects.annotate(quantity=Sum('items__quantity')).filter(
        Q(hide=False) & Q(deleted=False),
        Q(stock=False) | Q(quantity__gte=1))
    return render_to_response('equipment/hire.html', {
           'categories_list': categories_list,
           'types_list': types_list,
           }, context_instance=RequestContext(request))

生成的 SQL 查询

SELECT "equipment_type"."id" [...] FROM "equipment_type" LEFT OUTER JOIN
    "equipment_subcategory" ON ("equipment_type"."subcategory_id" =
    "equipment_subcategory"."id") LEFT OUTER JOIN "equipment_item" ON
    ("equipment_type"."id" = "equipment_item"."type_id") WHERE 
    ("equipment_type"."hide" = False AND "equipment_type"."deleted" = False )
    AND ("equipment_type"."stock" = False )) GROUP BY "equipment_type"."id"
    [...] HAVING SUM("equipment_item"."quantity") >= 1

预期的 SQL 查询

SELECT
    *
FROM
    equipment_type
LEFT JOIN (
    SELECT type_id, SUM(quantity) AS qty
    FROM equipment_item
    GROUP BY type_id
) T1
ON id = T1.type_id
WHERE hide=0 AND deleted=0 AND (T1.qty > 0 OR stock=0)

---

编辑:我添加了预期的 SQL 查询(没有设备子类别的连接)

Answer 1

尝试添加括号以明确指定您的分组？正如您已经知道的那样，filter() 的多个参数只是通过底层 SQL 中的 AND 连接。

最初你有这个过滤器:

[...].filter(
    Q(hide=False) & Q(deleted=False),
    Q(stock=False) | Q(quantity__gte=1))

如果你想要 (A & B) & (C | D) 那么这应该可行:

[...].filter(
    Q(hide=False) & Q(deleted=False) &
    (Q(stock=False) | Q(quantity__gte=1)))