Django 通过多对多字段交集过滤对象

Question

Hello,

Can some good person give me advice on how to get a queryset of ordered objects by intersecting a many-to-many field with a given one object's many-to-many field?

For example I have:

class Video(models.Model):
tags = models.ManyToManyField(Tag, blank=True)

...

class Tag(models.Model):
name = models.CharField(max_length=64)

...

I select one Video object and would like to have first ten objects that have most similar tags set to show like related videos.

Thanks in advance!

Answer 1

I made a simple example, this should work

tag1 = Tag.objects.create(name="test video") #create a tag
video1 = Video.objects.create() #create a video
video1.tags.add(tag1) #add tag to video

video_query = Video.objects.filter(tags__name="test video")
print("query",video_query)

Now in this example its only 1 tag but if you have 100 tags put [:11] after video_query = Video.objects.filter(tags__name="test video")[:11]

This will give you the exact match.

If you use:

 video_query = Video.objects.filter(tags__in=example_video.tags.all())

You will get a query with all the videos with at least 1 matching tag, if a video has 2 matching tags it will be present 2 times in the query. You can fetch the videos which are present multiple times in the query. You need to exclude example_video from the query