DRF全部查询基础示例

    from django.db.models import Q, F, Sum, Avg, Count, Min, Max
        from rest_framework.response import Response
    from rest_framework.views import APIView

    class ShowView(APIView):
        def get(self, request):

            # 查询年龄等于19的数据
            user = User.objects.filter(age=19)
            print(user)
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            # 查询全部数据
            user = User.objects.all()
            print(user)
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            # 查询年龄等于19的数据的个数
            user = User.objects.filter(age=19).count()
            print(user,'--------------------------------')
            return Response('ok')

            # 查询年龄不等于19的全部数据
            user = User.objects.exclude(age=19)
            print(user)
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            # 查询一个字段是否包含要查询的关键字
            user = User.objects.filter(classrooms__address__contains='庆')
            print(user)
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            # startswith,endswith 以指定值开头或结尾
            user = User.objects.filter(classrooms__address__startswith='昌')
            print(user)
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            user = User.objects.filter(classrooms__address__endswith='区')
            print(user)
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            # 查询一个字段是否为空
            user = User.objects.filter(age__isnull=False)
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            # 范围查询
            # in  在范围内    range  相当于between...and...
            user = User.objects.filter(age__in =[ 1, 13,18, 19, 22])
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            user = User.objects.filter(age__range=[10, 20])
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            # ⽐较查询：
            # gt　　 　　 ⼤于
            # gte　　　　 ⼤于等于
            # lt　　 　　 ⼩于
            # lte　　　　 ⼩于等于
            # exclude　　不等于

            # F对象和Q对象
            # ⽐较两个字段对象之间的关系⽤F对象。（F对象可以进⾏运算）
            user = User.objects.filter(age__gte=F('hight'))
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            user = User.objects.filter(age__gte=F('hight') * 2)
            user_obj = UserSer(user, many=True)
            return Response(user_obj.data)

            class HightsView(APIView):

            def get(self, request):
            user_obj = User.objects.filter(Q(hight__gte=150) and Q(hight__lte=170) | Q(age__lt=20))

                ser = UserSer(user_obj, many=True)
                return Response(ser.data)

            # 聚合函数
            # 使⽤aggregate()过滤器调⽤聚合函数。聚合函数包括：Avg 平均，Count 数量，Max 最⼤，
            # Min 最⼩，Sum 求和
            user = User.objects.aggregate(sum=Sum('age'))
            print(user)
            return Response('ok')

            user = User.objects.aggregate(avg=Avg('age'))
            print(user)
            return Response('ok')

            user = User.objects.aggregate(count=Count('age'))
            print(user)
            return Response('ok')

            user = User.objects.aggregate(min=Min('age'))
            print(user)
            return Response('ok')

            user = User.objects.aggregate(max=Max('age'))
            print(user)
            return Response('ok')