Querying Embedded/Nested Documents

These two filters look alike, yet on the same data the first returns two users and the second returns none.

db.users.find({ "address.city": "Anytown" }, { name: 1, _id: 0 })
db.users.find({ address: { city: "Anytown" } }, { name: 1, _id: 0 })

[ { name: 'John Doe' }, { name: 'Alice' } ]
[]

The difference lies in how each filter reads the address field. In the documents below, address holds a smaller document inside the main one, which is known as an embedded or nested document