# ORM
class ORMView(APIView):
    def get(self, request):
        """
        基本查询:
            查询单条数据 .get
            查询全部数据 .all
            计数 .count    过滤.filter
            查询除了XX  .exclude
        模糊查询:
            查询是否包含 contains
            以指定值结尾或开头 startwith、endwith
        空查询:
            是否为空 isnull
        范围查询:
            列举的值 in
            在范围内 range
        比较查询:
            大于 gt   小于lt
            大于等于 gte  小于等于 lte
            不等于 exclude
        F和Q:
            比较两个字段之间的关系用F
            使用逻辑运算符时 用Q
        聚合函数:
            Avg  Sum  Max  Min
            注意:关键字首字母大写
        排序:
            使用order_by对结果进行排序  字段前加‘-’降序
        关联查询:
            一对多
            ... ...
        """
        # 基础orm操作
        # user = User.objects.get(name="王凯玉")
        # user = User.objects.all()
        # user = User.objects.filter(name="ppp").count()
        # user = User.objects.exclude(name="ppp")
        # user = User.objects.filter(name__contains="p")
        # user = User.objects.filter(name__endswith="然")
        # user = User.objects.filter(name__isnull=True)
        # user = User.objects.filter(age__range=[10, 20])
        # user = User.objects.filter(age__lt=19)
        # user = User.objects.filter(age=F("height"))
        # user = User.objects.filter(Q(age__gt=100) & Q(height__gte=170))
        # user = User.objects.aggregate(Sum(‘age‘))
        # user = User.objects.all().order_by("-height")
        # x = Classroom.objects.get(id=1)
        # p = x.user_set.all()
        # x_ser = ShowUserSerializer(p, many=True)原文:https://www.cnblogs.com/wangkaiyu/p/14153074.html