Question

目前，我正在使用Django和配置有Djongo的MongoDB。

这些是我的2个课程：

class Machine (models.Model):
machine_type = models.ForeignKey(MachineType, related_name ='machine_types', on_delete = models.CASCADE)
machine_customer = models.ForeignKey(Customer, related_name='machine_customers', on_delete = 
models.CASCADE)
machine_serial_number = models.CharField(max_length = 255)
#
def __str__(self):
    return self.machine_serial_number

class Part (models.Model):
part_id = models.CharField(max_length = 255)
machine_serial_number = models.ForeignKey(Machine, related_name='parts', on_delete = models.CASCADE)
machining_start = models.DateTimeField()
machining_end = models.DateTimeField()
quality = models.CharField(max_length = 3)
#
def __str__(self):
    return self.part_id

我一直在尝试执行以下查询，以查找每台机器上生产的不良零件的数量。

results=Machine.objects.values('machine_serial_number')
.annotate(part_nok=Count('parts', filter=Q(parts__quality__icontains='NIO')))

但是我仍然收到以下错误消息：

COUNT(CASE WHEN "eda_main_part"."quality" iLIKE %(0)s THEN "eda_main_part"."id" ELSE NULL END) AS 
"part_nok" FROM "eda_main_machine" LEFT OUTER JOIN "eda_main_part" ON ("eda_main_machine"."id" = 
"eda_main_part"."machine_serial_number_id") GROUP BY "eda_main_machine"."machine_serial_number"  
LIMIT 21
Version: 1.2.31

理想情况下，我希望收到类似的东西：

{machine1:#111222, part_nok:121, part_ok:68, ... and so on }

相反，通过省略过滤器执行以下查询

results=Machine.objects
.values('machine_serial_number').annotate(part_nok=Count( 'parts'))

一切正常。

我正在使用以下工具：

sqlparse==0.2.4
djongo==1.2.31
Django==2.2.6
python 3.7.4
MongoDb 4.2

在Djongo中使用过滤器进行计数注释

0 个答案: