ORM作业

from django.shortcuts import render
from django.http import HttpResponse
from .models import Student,Teacher,Score,Course
from django.db.models import Avg,Sum,Count,Q,F,Min,Max

def index(request):
    #1. 查询平均成绩大于60分的同学的id和平均成绩；
    students = Student.objects.annotate(score_avg = Avg("score__number")).filter(score_avg__gt=60).values(‘id‘,‘score_avg‘)
    for student in students:
        print(student)
    return HttpResponse(‘123‘)

def index2(request):
    #2. 查询所有同学的id、姓名、选课的数量、总成绩；
    students = Student.objects.annotate(course_num = Count(‘score‘),total = Sum(‘score__number‘)).values(‘id‘,‘course_num‘,‘total‘,‘name‘)
    for student in students:
        print(student)
    return HttpResponse(‘456‘)

def index3(request):
    #3.查询姓“李”的老师的个数；
    count = Teacher.objects.filter(name__startswith=‘李‘).count()
    print(count)
    return HttpResponse(‘789‘)

def index4(request):
    #4.查询没学过“李老师”课的同学的id、姓名；
    students = Student.objects.exclude(score__course__teacher__name = ‘李老师‘).values(‘id‘,‘name‘)
    for student in students:
        print(student)
    return HttpResponse(‘741‘)

def index5(request):
    # 5.查询学过课程id为1和2的所有同学的id、姓名
    students = Student.objects.filter(score__course__in=[1.2]).values(‘id‘,‘name‘)
    for student in students:
        print(student)
    return HttpResponse(‘852‘)

def index6(request):
    # 6.查询学过“黄老师”所教的所有课的同学的学号、姓名；
    # 1. 首先先找到每一位学生学习的黄老师课程的数量；A
    # 2. 在课程的表中找到黄老师教的课程的数量；B
    # 3. 判断A是否等于B，如果相等，那么意味着这位学生学习了黄老师教的
    # 所有课程，如果不想等，那么意味着这位学生没有学完黄老师教的所有课程
    rows = Student.objects.annotate(nums =Count("score__course",filter=Q(score__course__teacher__name=‘黄老师‘))).filter(nums =Course.objects.filter(teacher__name=‘黄老师‘).count()).values(‘id‘,‘name‘)
    for row in rows:
        print(row)
    return HttpResponse(‘00000‘)

def index7(request):
    # 7. 查询所有课程成绩小于60分的同学的id和姓名；
    students = Student.objects.filter(score__number__lt=60).values(‘id‘,‘name‘)
    print(students)
    for student in students:
        print(student)
    return HttpResponse(‘159‘)

def index8(request):
    # 8. 查询没有学全所有课的同学的id、姓名；
    # students = Student.objects.annotate(num=Count(F(‘score__course‘)))
    students = Student.objects.annotate(num = Count(F(‘score__course‘))).filter(num__lt=Course.objects.count()).values(‘id‘,‘name‘)
    print(students)
    return HttpResponse(‘index8‘)

def index9(request):
    # 9.查询所有学生的姓名、平均分，并且按照平均分从高到低排序；
    students =Student.objects.annotate(avg = Avg(‘score__course‘)).order_by(‘-avg‘).values(‘name‘,‘avg‘)
    for student in students:
        print(student)
    return HttpResponse(‘index9‘)

def index10(request):
    # 10.查询各科成绩的最高和最低分，以如下形式显示：课程ID，课程名称，最高分，最低分：
    courses = Course.objects.annotate(min = Min("score__number"),max=Max("score__number")).values(‘id‘,‘name‘,‘min‘,‘max‘)
    for course in courses:
        print(course)
    return HttpResponse("index10")

def index11(request):
    # 11. 查询每门课程的平均成绩，按照平均成绩进行排序；
    courses = Course.objects.annotate(avg =Avg("score__number")).order_by("avg").values("id",‘name‘,‘avg‘)
    for course in courses:
        print(course)
    return HttpResponse(‘index11‘)

def index12(request):
    # 12. 统计总共有多少女生，多少男生
    rows = Student.objects.aggregate(male_num=Count(‘gender‘,filter=Q(gender=1)),female_num =Count(‘gender‘,filter=Q(gender=2)))
    print(rows)
    return HttpResponse(‘index12‘)

def index13(request):
    # 13.将“黄老师”的每一门课程都在原来的基础之上加5分；
    rows = Score.objects.filter(course__teacher__name=‘黄老师‘).update(number=F(‘number‘)+5)
    print(rows)
    return HttpResponse(‘index13‘)

def index14(request):
    #14 .查询两门以上不及格的同学的id、姓名、以及不及格课程数
    students = Student.objects.annotate(bad_num = Count(‘score__number‘,filter=Q(score__number__lt=60))).filter(bad_num__gte=2).values(‘id‘,‘name‘,‘bad_num‘)
    for student in students:
        print(student)
    return HttpResponse(‘index14‘)

def index15(request):
    #15. 查询每门课的选课人数；
    courses = Course.objects.annotate(student_num = Count(‘score__student‘)).values(‘name‘,‘student_num‘)
    for course in courses:
        print(course)
    return HttpResponse(‘index15‘)