Python Sqlalchemy在查询中计算重复的结果

Question

我有一个查询

allcategory =  db.session.query(func.count(marketItem.subcategory).label("help"),Subcategories.subname1)
allcategory = allcategory.join(Subcategories)
allcategory = allcategory.filter(marketItem.subcategory == Subcategories.id)
allcategory = allcategory.filter(marketItem.vendor_id==vendorprofile.id)
allcategory = allcategory.group_by(marketItem.id)
for allcat in allcategory.all():
    print(allcat)

那将结果输出为

(1, 'Consoles')
(1, 'Consoles')
(1, 'Paintings')
(1, 'Paintings')
(1, 'Paintings')

我希望他们成为

(2, 'Consoles')
(3, 'Paintings')

如果它也可以用常规的sql术语来解释，那也会有所帮助。

Answer 1

您应按Subcategory.subname1分组：

allcategory =  db.session.query(func.count(marketItem.subcategory).label("help"),
                                Subcategories.subname1)
allcategory = allcategory.join(Subcategories)
allcategory = allcategory.filter(marketItem.subcategory==Subcategories.id)
allcategory = allcategory.filter(marketItem.vendor_id==vendorprofile.id)
allcategory = allcategory.group_by(Sucategories.subname1) # < change here
for allcat in allcategory.all():
    print(allcat)

在SQL中，您必须按照未汇总的字段进行分组 - 在本例中为Subcategories.subname1。