[英]Django query filter combining AND and OR with Q objects don't return the expected results
我尝试在使用Q对象的过滤器中组合AND和OR。 它看起来像| 表现得像一个AND。 这与先前的注释有关,该注释在同一查询中运行而不是在子查询中运行。
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))
产生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(没有在equipment_subcategory上的连接)
尝试添加括号以明确指定您的分组? 正如您已经想到的那样, 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)和(C | D)那么这应该工作:
[...].filter(
Q(hide=False) & Q(deleted=False) &
(Q(stock=False) | Q(quantity__gte=1)))
这个答案很晚,但可能会对很多人有所帮助。
[...].filter(hide=False & deleted=False)
.filter(Q(stock=False) | Q(quantity__gte=1))
这会产生类似的东西
WHERE (hide=0 AND deleted=0 AND (T1.qty > 0 OR stock=0))
好的,这里或#django没有成功。 所以我选择使用原始SQL查询来解决这个问题......
这里的工作代码:
types_list = Type.objects.raw('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)
')
这是我复杂查询的例子,希望你觉得它有用
or_condition = Q()
and_condition = Q(company=request.user.profile.company)
for field in MyModel._meta.get_fields():
if field.name != 'created_on' and field.name != 'company':
or_condition.add(
Q(**{"{}__icontains".format(field.name): query}), Q.OR)
and_condition.add(or_condition2, Q.AND)
MyModel.objects.filter(and_condition)
这种方法的问题是你的or_condition
有一个empty (AND: )
or_condition
。 它根本不会影响查询,但它让我很烦恼! 我目前的解决方案如下
import operator
from functools import reduce
and_condition = Q(company=request.user.profile.company)
or_condition = reduce(operator.or_, (Q(**{"{}__icontains".format(field.name): query})
for field in MyModel._meta.get_fields() if field.name != 'created_on' and field.name != 'company'))
and_condition.add(or_condition, Q.AND)
MyModel.objects.filter(and_condition)
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