[
    {
        "$lookup": {
            "from": "participant",
            "localField": "participantId",
            "foreignField": "_id",
            "as": "participants"
        }
    },
    {
        "$unwind": {
            "path": "$participants",
            "preserveNullAndEmptyArrays": true
        }
    },
    {
        "$lookup": {
            "from": "subscription",
            "localField": "participantId",
            "foreignField": "userId",
            "as": "subscriptions"
        }
    },
    {
        "$unwind": {
            "path": "$subscriptions",
            "preserveNullAndEmptyArrays": true
        }
    },
    {
        "$lookup": {
            "from": "subscriptionPlan",
            "localField": "subscriptions.planId",
            "foreignField": "_id",
            "as": "subscriptionPlans"
        }
    },
    {
        "$unwind": {
            "path": "$subscriptionPlans",
            "preserveNullAndEmptyArrays": true
        }
    },
    {
        "$match": {
            "nutritionistID": {
                "$oid": "64782249defe1c75d7689cbd"
            }
        }
    },
    {
        "$match": {
            "subscriptions.planId": {
                "$exists": true
            }
        }
    },
    {
        "$match": {
            "participants": {
                "$exists": true
            }
        }
    },
    {
        "$match": {
            "participants": {
                "$exists": true
            }
        }
    },
    {
        "$match": {
            "active": true
        }
    }
]




//query 2
[
    {
        "$lookup": {
            "from": "participant",
            "localField": "participantId",
            "foreignField": "_id",
            "as": "participants"
        }
    },
    {
        "$unwind": {
            "path": "$participants",
            "preserveNullAndEmptyArrays": true
        }
    },
    {
        "$lookup": {
            "from": "subscription",
            "localField": "participantId",
            "foreignField": "userId",
            "as": "subscriptions"
        }
    },
    {
        "$unwind": {
            "path": "$subscriptions",
            "preserveNullAndEmptyArrays": true
        }
    },
    {
        "$lookup": {
            "from": "subscriptionPlan",
            "localField": "subscriptions.planId",
            "foreignField": "_id",
            "as": "subscriptionPlans"
        }
    },
    {
        "$unwind": {
            "path": "$subscriptionPlans",
            "preserveNullAndEmptyArrays": true
        }
    },
    {
        "$match": {
            "nutritionistID": {
                "$oid": "64782249defe1c75d7689cbd"
            }
        }
    },
    {
        "$match": {
            "subscriptions.planId": {
                "$exists": false
            }
        }
    },
    {
        "$match": {
            "participants": {
                "$exists": true
            }
        }
    },
    {
        "$match": {
            "participants": {
                "$exists": true
            }
        }
    },
    {
        "$match": {
            "active": true
        }
    }
]



for tavishi table is -> userNutrionistMapping