Django的選擇不同

Question

models.py

class Category(models.Model): 
    name = models.CharField(max_length=50) 

    def __unicode__(self): 
     return self.name 

class Gender(models.Model): 
    name = models.CharField(max_length=50) 

    def __unicode__(self): 
     return self.name 

class Post(models.Model): 
    name = models.CharField(max_length=50) 
    categories = models.ManyToManyField(Category) 
    genders = models.ManyToManyField(Gender) 

    def __unicode__(self): 
     return self.name 

view.py：

def index(request): 
    posts = Post.objects.filter(genders=1) 

    categories = Category.objects.filter(post__genders=1) 
           .exclude(post=None).order_by('-sort') 

爲什麼我得到的同一類別的3倍，如果有3個職位，其中性別等於1？我只需要類別1的時間我喜歡「選擇不同」的選擇 - 我該怎麼做？

Answer 1

您是否嘗試將.distinct()附加到查詢集？

categories = Category.objects.filter(post__genders=1).exclude(post= 
     None).order_by('-sort').distinct()