``` javascript
db.users.find({"username" : "jozef", "age" : 27})
db.users.find({}, {"username" : 1, "email" : 1})
db.users.find({}, {"fatal_weakness" : 0})
db.users.find({}, {"username" : 1, "_id" : 0})
db.users.find({"age" : {"$gte" : 18, "$lte" : 30}})
start = new Date("01/01/2007")
db.users.find({"registered" : {"$lt" : start}})
db.users.find({"username" : {"$ne" : "jozef"}})
db.users.find({"user_id" : {"$in" : [12345, "jozef"]}})
db.users.find({"id_num" : {"$mod" : [5, 1]}})
db.users.find({"id_num" : {"$not" : {"$mod" : [5, 1]}}})
db.users.find({"name" : {"$regex" : /aga/i } })
db.users.find({"name" : /aga(ta)?/i})
```