Django將具有唯一外鍵ID的所有值相加，並用相關表中的字段壓縮它們

Question

我想執行與此類似的操作（即，在付款表中獲得不同事件金額的總和，然后按事件明細和為其支付的總金額對付款進行分組。還將獲得用戶及其為事件支付的金額）在Django中使用PostgreSQL。

我的模型如下：

class UserProfile(User):
    onames = models.CharField(max_length=30, blank=True)
    phoneNumber = models.CharField(max_length=15, blank=True)
    regNo = models.CharField(max_length=15)
    designation = models.CharField(max_length=3,choices=DESIGNATION_CHOICES, default='MEM')
    image = models.ImageField(max_length=100,upload_to='photos/%Y/%m/%d', blank=True, null=True, default='photos/2010/03/placeholder.jpg')
    course = models.CharField(max_length=30, blank=True, null=True)
    timezone = models.CharField(max_length=50, default='Africa/Nairobi')
    smsCom = models.BooleanField()
    mailCom = models.BooleanField()

class Payments(models.Model):
    username = models.ForeignKey(UserProfile, related_name='payer')
    receiptNo = models.CharField(max_length=30, primary_key=True)
    particulars = models.CharField(max_length=50)
    date = models.DateField(auto_now_add=True)
    amount = models.FloatField(max_length=99, blank=True)
    eventID = models.ForeignKey('events', null=True, blank=True)
    receiver = models.ForeignKey(UserProfile, related_name='receiver')
    deleted = models.BooleanField()

class events(models.Model):
    eventName  = models.CharField(max_length=100)
    eventID =  models.AutoField(primary_key=True)
    details = models.TextField()
    attendanceFee = models.FloatField(max_length=99)
    date = models.DateField()
    username = models.ManyToManyField(UserProfile, related_name='user')
    eventposter = models.ForeignKey(UserProfile, related_name='event_poster')
    deleted = models.BooleanField()

Answer 1

經過一陣神經nerve，解決方案是將查詢分為2個，即一個用於分組和求和，另一個用於獲取匹配值。

有關分組和求和，請參見此處