Django queryset - 添加HAVING约束

Question

我已经使用Django几年了但是我今天在HAVING为a 添加约束而苦苦挣扎GROUP BY.

我的查询集如下:

crm_models.Contact.objects\
.filter(dealercontact__dealer__pk__in=(265,),
         dealercontact__activity='gardening',
         date_data_collected__gte=datetime.date(2012,10,1),
         date_data_collected__lt=datetime.date(2013,10,1))\
.annotate(nb_rels=Count('dealercontact'))

这给了我以下MySQL查询:

SELECT *
FROM `contact` 
LEFT OUTER JOIN `dealer_contact` ON (`contact`.`id_contact` = `dealer_contact`.`id_contact`) 
WHERE (`dealer_contact`.`active` = True 
   AND `dealer_contact`.`activity` = 'gardening'  
   AND `contact`.`date_data_collected` >= '2012-10-01'  
   AND `contact`.`date_data_collected` < '2013-10-01'
   AND `dealer_contact`.`id_dealer` IN (265)) 
GROUP BY `contact`.`id_contact`
ORDER BY NULL;

我会得到这个HAVING约束我需要的东西:

HAVING SUM(IF(`dealer_contact`.`type`='customer', 1, 0)) = 0 

如何使用Django Queryset修复此问题？我在这个实例中需要一个查询集.

这里我只使用注释才能GROUP BY开启contact.id_contact.

编辑:我的目标是获得在dealercontact中没有"客户"关系但具有"ref"关系的联系人(当然根据WHERE子句).

楷模

class Contact(models.Model):
    id_contact = models.AutoField(primary_key=True)
    title = models.CharField(max_length=255L, blank=True, choices=choices_custom_sort(TITLE_CHOICES))
    last_name = models.CharField(max_length=255L, blank=True)
    first_name = models.CharField(max_length=255L, blank=True)
    [...]
    date_data_collected = models.DateField(null=True, db_index=True)

class Dealer(models.Model):
    id_dealer = models.AutoField(primary_key=True)
    address1 = models.CharField(max_length=45L, blank=True)
    [...]

class DealerContact(Auditable):
    id_dealer_contact = models.AutoField(primary_key=True)
    contact = models.ForeignKey(Contact, db_column='id_contact')
    dealer = models.ForeignKey(Dealer, db_column='id_dealer')
    activity = models.CharField(max_length=32, choices=choices_custom_sort(ACTIVITIES), db_index=True)
    type = models.CharField(max_length=32, choices=choices_custom_sort(DEALER_CONTACT_TYPE), db_index=True)

Answer 1

我通过在DealerContact:is_ref和中添加两个二进制字段来解决这个问题is_customer.

如果type='ref'那时is_ref=1和is_customer=0.否则,如果type='customer'再is_ref=0和is_customer=1.

因此,我现在可以使用annotate(nb_customers=Sum('is_customer'))然后使用filter(nb_customers=0).

最终的查询集包括:

Contact.objects.filter(dealercontact__dealer__pk__in=(265,),  
                       dealercontact__activity='gardening', 
                       date_data_collected__gte=datetime.date(2012,10,1),
                       date_data_collected__lt=datetime.date(2013,10,1))\
               .annotate(nb_customers=Sum('dealercontact__is_customer'))\
               .filter(nb_customers=0)