5EHIF_Meyringer_Wishlist_Mongo_Queries.json

db.wishlist.deleteMany({
  "child.firstname": 'Zachariah',
  "child.lastname": 'Downer',
  year: 2023
});

db.wishlist.updateMany(
  {
    "child.firstname": 'Zachariah',
    "child.lastname": 'Downer',
    year: 2023
  },
  {
    $set: {
      "items.$[elem].currentprice": 100.00
    }
  },
  {
    arrayFilters: [{"elem.name": "Steamers White"}]
  }
);

## First find
db.wishlist.find({});

## Second find
db.wishlist.find({
  "child.firstname": "Ninth",
  "child.lastname": "Child"
});

## Third find
db.wishlist.aggregate([
  {
    $unwind: "$items"
  },
  {
    $group: {
      _id: {
        year: "$year",
        firstname: "$child.firstname",
        lastname: "$child.lastname"
      },
      items: {
        $push: {
          id: "$items.id",
          name: "$items.name",
          currentprice: "$items.currentprice"
        }
      },
      itemCount: { $sum: 1 }
    }
  },
  {
    $project: {
      _id: 0,
      year: "$_id.year",
      child: {
        $concat: ["$_id.firstname", " ", "$_id.lastname"]
      },
      itemCount: 1
    }
  }
]);

## Forth Querie
db.wishlist.aggregate([
  {
    $unwind: "$items"
  },
  {
    $group: {
      _id: {
        year: "$year",
        firstname: "$child.firstname",
        lastname: "$child.lastname"
      },
      items: {
        $push: {
          id: "$items.id",
          name: "$items.name",
          currentprice: "$items.currentprice"
        }
      },
      avgItemPrice: { $avg: "$items.currentprice" }
    }
  },
  {
    $project: {
      _id: 0,
      year: "$_id.year",
      child: {
        $concat: ["$_id.firstname", " ", "$_id.lastname"]
      },
      avgItemPrice: 1
    }
  }
]);


## With ref
db.wishlist.deleteMany({
  "child": 1,
  "year": 2000
});

db.wishlist.updateMany({
  "child": 1,
  "year": 2000
  },
  {
    $set: {
      "items.$[elem].currentprice": 100.00
    }
  },
  {
    arrayFilters: [{"elem.name": "Steamers White"}]
  }
);

## First find
db.wishlist.find({});

## Second find
db.child.find({
  "child.firstname": "Zachariah",
  "child.lastname": "Downer"
});

## Third find
db.wishlist.createIndex({ "child.id": 1 });
db.wishlist.aggregate([
  {
    $unwind: "$items"
  },
  {
    $lookup: {
      from: "child",
      localField: "child",
      foreignField: "id",
      as: "childInfo"
    }
  },
  {
    $unwind: "$childInfo"
  },
  {
    $group: {
      _id: {
        year: "$year",
        firstname: "$childInfo.firstname",
        lastname: "$childInfo.lastname"
      },
      items: {
        $push: {
          id: "$items.id",
          name: "$items.name",
          currentprice: "$items.currentprice"
        }
      },
      itemCount: { $sum: 1 }
    }
  },
  {
    $project: {
      _id: 0,
      year: "$_id.year",
      child: {
        $concat: ["$_id.firstname", " ", "$_id.lastname"]
      },
      itemCount: 1
    }
  }
]);


## Forth Querie
db.wishlist.aggregate([
  {
    $unwind: "$items"
  },
  {
    $lookup: {
      from: "child",
      localField: "child",
      foreignField: "id",
      as: "childInfo"
    }
  },
  {
    $unwind: "$childInfo"
  },
  {
    $group: {
      _id: {
        year: "$year",
        firstname: "$childInfo.firstname",
        lastname: "$childInfo.lastname"
      },
      items: {
        $push: {
          id: "$items.id",
          name: "$items.name",
          currentprice: "$items.currentprice"
        }
      },
      avgItemPrice: { $avg: "$items.currentprice" }
    }
  },
  {
    $project: {
      _id: 0,
      year: "$_id.year",
      child: {
        $concat: ["$_id.firstname", " ", "$_id.lastname"]
      },
      avgItemPrice: 1
    }
  }
]);