mongodb.txt

$root
$facet

$count
$limit
$lookup

pipline
$let
$expr
"$$secondUser"

$_id.name

$toDate

$inc

$$ROOT
------------------

count
groupby
limit
---

projection

-------------
Fields
The following operators can be used to update fields:

$currentDate: Sets the field value to the current date
$inc: Increments the field value
$rename: Renames the field
$set: Sets the value of a field
$unset: Removes the field from the document
Array
The following operators assist with updating arrays.

$addToSet: Adds distinct elements to an array
$pop: Removes the first or last element of an array
$pull: Removes all elements from an array that match the query
$push: Adds an element to an array

=========

{ "$match": {
"$expr": {
  "$and": [
    { "$eq": ["$patientId", "$$patientId"] },
    { "$eq": ["$branchId", "$$clinic_id"] }
  ]
},
"acknowleged": false
}}
result = company_collection.aggregate([
                {"$match": {"contacts.country": "India"}},
                {"$lookup": {
                    "from": "users",
                    "localField": "_id",
                    "foreignField": "company_id",
                    "as": "users",
                    "pipeline": [
                        { "$match": {
                        "$expr": {
                            "$and": [
                                { "$gte": ["created_datetime", "2023-02-23T00:00:00+0000"] },
                                { "$lte": ["created_datetime", "2023-02-23T00:00:00+0000"] }
                            ]
                        }
                    }}, {"$project": {"email": 1}}
                    ]
                }},
                {"$unwind": "$users"},
                {"$project": {
                    'name': 1,
                    'email': "$users.email"
                }},
                {"$count": 'total_count'},
                {"$project": {
                    'total_count': "$total_count"
                }},