Python Django集团(按日期和类别计数)
示例模型Python Django集团(按日期和类别计数),python,mysql,django,Python,Mysql,Django,示例模型 class Category(models.Model) name = models.CharField() class CategoryItem(models.Model): category = models.ForeignKey(Category) name = models.CharField() quantity = models.IntField() at = models.DateTimeField() Categories:
class Category(models.Model)
name = models.CharField()
class CategoryItem(models.Model):
category = models.ForeignKey(Category)
name = models.CharField()
quantity = models.IntField()
at = models.DateTimeField()
Categories:
1, Category #1
2, Category #2
3, Category #3
Items:
ID,NAME,CATEGORY_ID,QUANTITY,AT
1,Item #1,1,100,2017.1.1
2,Item #2,1,200,2017.1.3
3,Item #3,1,300,2017.1.3
4,Item #4,2,400,2017.1.10
5,Item #5,3,500,2017.1.10
我怎样才能按日标注并计算每个类别的“数量”
像这样
2017.1.1
- Category #1
- Quantity: 100
2017.1.3
- Category #1
- Quantity: 500
2017.1.10
- Category #2
- Quantity: 400
- Category #3
- Quantity: 500
如果我理解您的问题,您需要一个带有GROUPBY和count(以及内部联接)的Django查询 试着这样做:
CategoryItem.objects.filter(CategoryItem__Category__isnull=False).values('at,name').annotate(total=Count('quantity')).order_by('at')
欢迎来到堆栈溢出!请拿着这本书,四处看看,特别是通读一下。你上面问的问题一点也不清楚,你能编辑你的问题来澄清吗?也许你希望这里有免费的代码编写服务?