如果该值为null，则Postgre SQL会忽略过滤条件 [英] Postgre SQL ignore the filtering condition if the value is null

问题描述

我将以下三个变量传递给查询 A，B和C .

I have the following three variables passed to the query A,B and C.

A，B和C可以采用任何值，包括null.

A, B and C can take any values including null.

当我运行下面的查询集时，如果A，B或C中的值为空，它应该忽略条件

When I run the below queryset, it should ignore the condition if the value in A,B or C is null

queryset = User.objects.values().filter(A_name=A, B_name=B, C_name =C)

例如，如果C值传入null，则查询的行为应类似于

For example, if C value passed in null then the query should behave like

queryset = User.objects.values().filter(A_name=A, B_name=B)

如果C和A值传入null，则查询的行为应类似于

And if C and A value passed in null then the query should behave like

queryset = User.objects.values().filter(B_name=B)

我不想编写所有9种组合并编写查询.我有什么办法可以轻松做到吗?.

I dont want to write all the 9 combinations and write a query. Is there any way I can do it easily?.

推荐答案

您可以将参数保留为dict，并仅将不等于None的参数发送给filter()方法:

You can keep arguments as dict and send to filter() method only those of them which are not equal to None:

arguments = {"A_name": A, "B_name": B, "C_name": C}
arguments_without_null = {k: v for k, v in arguments.items() if v is not None}
queryset = User.objects.values().filter(**arguments_without_null)

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