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dolaxi

Django 或查询

  •  
  •   dolaxi Dec 29, 2019 2071 views
    This topic created in 2314 days ago, the information mentioned may be changed or developed.

    模型:

    class Goods(models.Model): name=models.CharField(max_length=50,verbose_name='名称') image = models.CharField(max_length=250,verbose_name='封面图') is_banner = models.BooleanField(default=False,verbose_name='是否是轮播图') nav = models.ForeignKey('Nav',verbose_name='所属分类导航') 

    视图:

    class HomeView(request): banner_queryset=Goods.objects.filter(is_banner=1)[:3] #首页 3 条轮播图数据 clothes_queryset=Goods.objects.filter(nav_id=1)[:5] #首页 5 条衣服数据 

    这两个查询语句,合成一个查询语句,如何写?

    banner_queryset 、clothes_queryset 这两个查询出的结果,有些数据可能是重合的

    9 replies    2019-12-29 21:43:28 +08:00
    uhian
        1
    uhian  
       Dec 29, 2019
    没有切片的可以 result = queryset1 | queryset2
    有切片操作的貌似不能这样
    实在不行将 clothes_queryset 加一个 exclude(id__in=[b.id for b in banner_queryset])?
    SingeeKing
        2
    SingeeKing  
    PRO
       Dec 29, 2019
    搜索关键字:Django F
    SingeeKing
        3
    SingeeKing  
    PRO
       Dec 29, 2019
    哦不,是 Django Q
    uhian
        4
    uhian  
       Dec 29, 2019
    @SingeeKing Q 也不能切片啊
    SingeeKing
        5
    SingeeKing  
    PRO
       Dec 29, 2019
    @uhian #4 他的切片可以直接用 limit 啊。。
    uhian
        6
    uhian  
       Dec 29, 2019
    @SingeeKing 切片不就是 LIMIT 么?还有别的操作?
    SingeeKing
        7
    SingeeKing  
    PRO
       Dec 29, 2019
    @uhian #6 Django 竟然不能直接 Limit……

    搜了一下官方的说法,https://groups.google.com/forum/#!topic/django-users/Q4KB5qPlGtA 似乎没办法直接合
    uhian
        8
    uhian  
       Dec 29, 2019
    @SingeeKing Django 的切片,也就是[:3],实际做数据查询也就是转成 SQL 就是 limit。
    Django 的 LIMIT 没啥问题,问题是两个带 LIMIT 的查询结果( QuerySet )直接求或,貌似是真不行。查询结果本身可以求或,还可以返回 distinct 结果。
    dolaxi
        9
    dolaxi  
    OP
       Dec 29, 2019
    @SingeeKing @uhian
    有切片确实不好操作,
    result = queryset1 | queryset2 我试了一下,貌似可以成功,看原生查询语句,好像没啥毛病
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