我是 Django 的新手。如何将 COALESCE sql 查询集写入 django orm。
query = 'SELECT COALESCE(max(CAST(order_no as UNSIGNED)), 0) as o,id from nanossc_Sales_master'
模型.py
class Sales_master(models.Model):
slno = models.IntegerField(blank=True, null=True)
order_no = models.CharField(max_length=50, blank=True, null=True)
type = models.CharField(max_length=50, blank=True, null=True)
customer_id = models.CharField(max_length=50, blank=True, null=True)
customer_name = models.CharField(max_length=50, blank=True, null=True)
brand_name = models.CharField(max_length=50, blank=True, null=True)
name = models.CharField(max_length=50, blank=True, null=True)
最佳答案
您可以使用 Coalesce
expression [Django-doc]和 Cast
expression [Django-doc]这里:
from django.db.models import Max, PositiveIntergerField, Value
from django.db.models.functions import Cast, Coalesce
Sales_master.objects.aggregate(
o=Coalesce(Max(Cast('order_no', output_field=PositiveIntergerField())), Value(0))
)
这将产生一个字典,其中一个键
'o'
映射到此聚合的结果。
关于django - 如何在 Django 中编写 sql COALESCE,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57444722/