如何在Django中动态组合OR查询过滤器？

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，这会导致：[<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？例如 [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