Question

我已经编写了以下代码，这些代码正确地按月份编号列出了我的地址集合，但这些是总数，我需要有效地添加一个条件，只返回结果，其中＆＃34; type = green＆＃ 34 ;.我无法确定如何只在符合这些标准时进行计数。

result = db.address.aggregate([{"$group":{"_id": { "$month": "$date" },
                       "count":{"$sum":1} } } ])

list_of_months = ["nothing", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]

result_sorted = sorted(result, key=lambda x: x['_id'], reverse=False)
for res in result_sorted:
    print(list_of_months[res['_id']], ": ", res['count'])

Answer 1

使用$match：

result = db.address.aggregate([{"$match": {"type": "green"}},
                               {"$group": {"_id": {"$month": "$date"},
                                           "count": {"$sum": 1}}}])

如何使用Pymongo按月查询MongoDB和组结果？

1 个答案: