Project 2

Statements for Creation of DB and insertion of values to collection is attached below.

1. db.order.aggregate([
{
    $lookup: {
     from: "customer",
     localField: "cust_id"
     }
},
{
     $group: {
     _id: "$cust_id",
      avgOrderValue: { $avg: "$ord_value" }
     }
}
])

2. db.customer.aggregate([
{
    $match: {
    created_at: { $gte: new Date(Date.now() - 1000 * 60 * 60 * 24 * 60) }
    }
},
{
    $lookup: {
    from: "order",
    localField: "_id"
    }
},
{
     $sort: { ord_value: -1 }
},
{
     $limit: 10
}
])

3. db.order.aggregate([
{
    $match: {
    created_at: {
    $gte: new Date(new Date().getFullYear(), new Date().getMonth(), 1),
    $lt: new Date(new Date().getFullYear(), new Date().getMonth() + 1, 1)
    }
  }
},
{
    $group: {
    _id: null,
    ord_value: { $sum: "$ord_value" }
    }
}
])

4. db.customer.aggregate([
{
    $group: {
    _id: "$city",
    customerCount: { $sum: 1 }
    }
},
{
     $sort: {
     customerCount: -1
     }
}
])

5. db.sellers.aggregate([
{
    $lookup: {
    from: "order",
    localField: "_id",
    as: "orders"
    }
},
{
    $lookup: {
    from: "customer",
    localField: "orders.cust_id",
    as: "customer"
    }
},
{
    $match: {
    "customer.city": "$city"
    }
},
{
    $group: {
    _id: "$cust_id",
    totalProductsSold: { $sum: "$orders.quantity" }
    }
},
{
   $sort: {
   totalProductsSold: -1
   }
}
])