CODEWITHSUNDEEP
python-3.xmongodbflaskpymongo
OptimusPrime
OptimusPrime

Reputation: 859

Month Aggregate PyMongo

How do you run a find query using PyMongo to aggregate by month?

I have tried the following:

searchdate = datetime.datetime.now().strftime("%Y-%m-%d")
eventscreated = list(db.event.find({"creator._id":ObjectId(myid)}, {"eventdate": {"$month": 'new Date("'+searchdate+'")'}} ))

results in:

pymongo.errors.OperationFailure: Unsupported projection option: eventdate: { $month: "new Date("2019-09-13")" }

Tried:

isodate = datetime.datetime.now()
isodate = isodate.replace(tzinfo=pytz.utc).isoformat()
eventscreated = list(db.event.find({"creator._id":ObjectId(myid)},
                                   {"eventdate": {"$month": 'ISODate("'+isodate+'")'}} ))

results in:

pymongo.errors.OperationFailure: Unsupported projection option: eventdate: { $month: "ISODate("2019-09-13T07:17:17.222737+00:00")" }

Can anyone help?

Upvotes: 0

Views: 198

Answers (2)

OptimusPrime
OptimusPrime

Reputation: 859

I managed to find the solution below which gives me what I need:

currmonth = datetime.datetime.now().strftime("%-m")
eventscreated = db.event.aggregate(
    [
        {"$addFields":
             {"month": {"$month": "$eventdate"}}
        },
        {"$match": {"month": int(currmonth), "creator._id": ObjectId(myid) } }
    ]
)

Upvotes: 0

Belly Buster
Belly Buster

Reputation: 8814

You need to use an aggregation pipeline with the $month operator. The snippet creates a test datetime for each day of the year and the aggregation pipeline counts the number of days in each month.

import pymongo
import datetime

db = pymongo.MongoClient()['mydatabase']

# Data setup
db.testdate.delete_many({})
for d in range(0, 365):
    dt = datetime.datetime(2019, 1, 1, 12, 0) + datetime.timedelta(days=d)
    db.testdate.insert_one({"Testdate": dt})

# Aggregation pipeline
months = db.testdate.aggregate(
    [
        {"$project":
             {"month": {"$month": "$Testdate"}}
        },
        {"$group":
             {"_id": "$month", "count": {"$sum": 1}}
        },
        {"$sort":
             {"_id": 1}
        }
    ]
)

for item in months:
    print(item)

Upvotes: 1

Related Questions