Querying on Array Elements in MongoDB

Review the following code, which demonstrates how to query array elements in MongoDB.

Find Documents with an Array That Contains a Specified Value

In the following example, "InvestmentFund" is not enclosed in square brackets, so MongoDB returns all documents within the products array that contain the specified value.

db.accounts.find({ products: "InvestmentFund"})

Find a Document by Using the $elemMatch Operator

Use the $elemMatch operator to find all documents that contain the specified subdocument. For example:

db.sales.find({
  items: {
    $elemMatch: { name: "laptop", price: { $gt: 800 }, quantity: { $gte: 1 } },
  },
})