Question

从示例中，您可以看到多个OR查询过滤器：

Article.objects.filter(Q(pk=1) | Q(pk=2) | Q(pk=3))

例如，这导致：

[<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]

但是，我想从列表中创建此查询过滤器。怎么做？

e.g。 [1, 2, 3] -> Article.objects.filter(Q(pk=1) | Q(pk=2) | Q(pk=3))

Answer 1

您可以按如下方式链接查询：

values = [1,2,3]

# Turn list of values into list of Q objects
queries = [Q(pk=value) for value in values]

# Take one Q object from the list
query = queries.pop()

# Or the Q object with the ones remaining in the list
for item in queries:
    query |= item

# Query the model
Article.objects.filter(query)

Answer 2

要构建更复杂的查询，还可以选择使用内置的Q（）对象的常量Q.OR和Q.AND以及add（）方法，如下所示：

list = [1, 2, 3]
# it gets a bit more complicated if we want to dynamically build
# OR queries with dynamic/unknown db field keys, let's say with a list
# of db fields that can change like the following
# list_with_strings = ['dbfield1', 'dbfield2', 'dbfield3']

# init our q objects variable to use .add() on it
q_objects = Q()

# loop trough the list and create an OR condition for each item
for item in list:
    q_objects.add(Q(pk=item), Q.OR)
    # for our list_with_strings we can do the following
    # q_objects.add(Q(**{item: 1}), Q.OR)

queryset = Article.objects.filter(q_objects)

# sometimes the following is helpful for debugging (returns the SQL statement)
# print queryset.query

Answer 3

使用python's reduce function编写Dave Webb答案的简短方法：

# For Python 3 only
from functools import reduce

values = [1,2,3]

# Turn list of values into one big Q objects  
query = reduce(lambda q,value: q|Q(pk=value), values, Q())  

# Query the model  
Article.objects.filter(query)

Answer 4

from functools import reduce
from operator import or_
from django.db.models import Q

values = [1, 2, 3]
query = reduce(or_, (Q(pk=x) for x in values))

Answer 5

使用sql IN语句可能更好。

Article.objects.filter(id__in=[1, 2, 3])

请参阅queryset api reference。

如果你真的需要用动态逻辑进行查询，你可以做这样的事情（丑陋+未经测试）：

query = Q(field=1)
for cond in (2, 3):
    query = query | Q(field=cond)
Article.objects.filter(query)

Answer 6

请参阅docs：

>>> Blog.objects.in_bulk([1])
{1: <Blog: Beatles Blog>}
>>> Blog.objects.in_bulk([1, 2])
{1: <Blog: Beatles Blog>, 2: <Blog: Cheddar Talk>}
>>> Blog.objects.in_bulk([])
{}

请注意，此方法仅适用于主键查找，但这似乎是您尝试执行的操作。

所以你想要的是：

Article.objects.in_bulk([1, 2, 3])

Answer 7

如果我们想以编程方式设置我们想要查询的db字段：

import operator
questions = [('question__contains', 'test'), ('question__gt', 23 )]
q_list = [Q(x) for x in questions]
Poll.objects.filter(reduce(operator.or_, q_list))

Answer 8

在此处使用包含reduce和or_运算符的解决方案，您如何通过乘法字段进行过滤。

from functools import reduce
from operator import or_
from django.db.models import Q

filters = {'field1': [1, 2], 'field2': ['value', 'other_value']}

qs = Article.objects.filter(
   reduce(or_, (Q(**{f'{k}__in': v}) for k, v in filters.items()))
)

P.S。 f是python3.6中新格式的字符串文字

Answer 9

您可以使用| =运算符以编程方式使用Q对象更新查询。

Answer 10

这个是动态pk列表：

pk_list = qs.values_list('pk', flat=True)  # i.e [] or [1, 2, 3]

if len(pk_list) == 0:
    Article.objects.none()

else:
    q = None
    for pk in pk_list:
        if q is None:
            q = Q(pk=pk)
        else:
            q = q | Q(pk=pk)

    Article.objects.filter(q)

Answer 11

我最近才知道的另一个选项 - QuerySet也会覆盖&，|，~等操作符。另一个答案是OR Q对象是这个问题的更好解决方案，但为了兴趣/参数，你可以这样做：

id_list = [1, 2, 3]
q = Article.objects.filter(pk=id_list[0])
for i in id_list[1:]:
    q |= Article.objects.filter(pk=i)

str(q.query)将返回一个包含WHERE子句中所有过滤器的查询。

Answer 12

For循环：

values = [1, 2, 3]
q = Q(pk__in=[]) # generic "always false" value
for val in values:
    q |= Q(pk=val)
Article.objects.filter(q)

减少：

from functools import reduce
from operator import or_

values = [1, 2, 3]
q_objects = [Q(pk=val) for val in values]
q = reduce(or_, q_objects, Q(pk__in=[]))
Article.objects.filter(q)

这两个都等同于Article.objects.filter(pk__in=values)

在values为空时考虑您想要什么很重要。许多以Q()作为起始值的答案将返回一切。 Q(pk__in=[])是更好的起点。这是一个始终失败的Q对象，可以通过优化程序很好地处理（即使对于复杂的方程式也是如此）。

Article.objects.filter(Q(pk__in=[]))  # doesn't hit DB
Article.objects.filter(Q(pk=None))    # hits DB and returns nothing
Article.objects.none()                # doesn't hit DB
Article.objects.filter(Q())           # returns everything

如果您想要在values为空时返回所有内容，则应与~Q(pk__in=[]) AND并确保该行为：

values = []
q = Q()
for val in values:
    q |= Q(pk=val)
Article.objects.filter(q)                     # everything
Article.objects.filter(q | author="Tolkien")  # only Tolkien

q &= ~Q(pk__in=[])
Article.objects.filter(q)                     # everything
Article.objects.filter(q | author="Tolkien")  # everything

重要的是要记住，Q()不是什么，也不是总是成功的Q对象。任何涉及此操作的操作都会将其完全删除。

Answer 13

容易..
来自django.db.models导入Q. 导入你的模型 args =（Q（visibility = 1）|（Q（visibility = 0）＆amp; Q（user = self.user）））#Tuple parameters = {} #dic order ='create_at' limit = 10

if

Answer 14

找到动态字段名称的解决方案：

def search_by_fields(value, queryset, search_in_fields):
    if value:
        value = value.strip()

    if value:
        query = Q()
        for one_field in search_in_fields:
            query |= Q(("{}__icontains".format(one_field), value))

        queryset = queryset.filter(query)

    return queryset

如何在Django中动态组合OR查询过滤器？

14 个答案: