MongoDB Aggregation Count of Group By Inner Array - mongodb

Question

I am using MongoDB 3.2.
Having trouble with this query ...
(Apologies in advance for the SQL-like syntax, I'm just learning Mongo coming from SQL)
I need to find the COUNT of documents where
"audit_event_type_id" : 1
shop2.date" BETWEEN "2014-10-01" AND "2015-09-01"
Grouping it by
shop2.facility_name
MONTH(shop2.date)
YEAR(shop2.date)
ORDER BY
count DESC
Is there a way to convert a string to date in the query? I know I am storing shop2.date as a string when it should be ISODate. If not, let's assume that it's an ISODate.
Here is a document sample :
{
"_id" : ObjectId("56b38f31967a337c432119cb"),
"audit_event_id" : 12382306,
"audit_event_type_id" : 2,
"group_id" : 3333489,
"applicant_id" : 3428508,
"service_credit_id" : 3804844,
"page_hit_id" : 43870954,
"shop1" : {
"facility_id" : 28,
"facility_name" : "Fake1",
"date" : "2014-08-13",
"time" : "07:00",
"expedite" : false,
"collect_biometrics" : false,
"block_id" : 364814,
"appointment_category" : "Renewal"
},
"shop2" : {
"facility_id" : 29,
"facility_name" : "Fake2",
"date" : "2014-08-07",
"time" : "07:00",
"expedite" : false,
"block_id" : 373614,
"appointment_category" : "Biometrics"
},
"created_at" : "2014-07-30 00:44:36",
"updated_at" : "2014-07-30 00:44:36",
"user_id" : 3242890,
"payment_id" : null,
"mission_id" : 24,
"affected_user_id" : null
}
Any help would be appreciated. Thanks!!
Update
I've updated all shop1.date & shop2.date to ISODate. Here is the new document sample :
{
"_id" : ObjectId("56b38f31967a337c432119cb"),
"audit_event_id" : 12382306,
"audit_event_type_id" : 2,
"group_id" : 3333489,
"applicant_id" : 3428508,
"service_credit_id" : 3804844,
"page_hit_id" : 43870954,
"shop1" : {
"facility_id" : 28,
"facility_name" : "Fake1",
"date" : ISODate("2014-08-13T00:00:00Z"),
"time" : "07:00",
"expedite" : false,
"collect_biometrics" : false,
"block_id" : 364814,
"appointment_category" : "Renewal"
},
"shop2" : {
"facility_id" : 29,
"facility_name" : "Fake2",
"date" : ISODate("2014-08-07T00:00:00Z"),
"time" : "07:00",
"expedite" : false,
"block_id" : 373614,
"appointment_category" : "Biometrics"
},
"created_at" : "2014-07-30 00:44:36",
"updated_at" : "2014-07-30 00:44:36",
"user_id" : 3242890,
"payment_id" : null,
"mission_id" : 24,
"affected_user_id" : null
}

Answer 1

You can use the aggregation framework in mongodb for this:
db.Collection.aggregate([
{ $match: {
audit_event_type_id: 1,
"shop2.date": { $gte: ISODate("2014-10-01T00:00:00.000Z"), $lt: ISODate("2015-09-01T00:00:00.000Z") } }
},
{ $group : {
_id : { "shop2.facility_name": "$shop2.facility_name", month: { $month: "$shop2.date" }, year: { $year: "$shop2.date" } },
count: { $sum: 1 } }
},
{ $sort : { count: -1 } }
])