$ db.collection.insert({name: "Yo"})
var name = {name: "Yea"}
$ db.collection.save(name)

$ db.collection.find().pretty()

$ db.collection.update({name: "a"}, {name: "updated"}) // replace
$ db.collection.update({name: "a", {$set:{name: "Yo"}}}) // field name only
$ db.users.update({name: "d"},{$set:{name: "d", age: 4}}, {upsert: true}) // ถ้าไม่เจอข้อมูลให้ insert
$ db.collection.update({role: "normal"}, {skill: "js"}, {multi: true}) // multi update

$ db.collection.remove({name: "a"}) // Maths
$ db.collection.remove({name: "a"}, 1) // ล่าสุด 1 อัน
$ db.collection.remove({}) // all

$ db.users.distinct("role")

$ db.users.count()
$ db.users.find({age: {$lte: 2}}).count()

$ db.users.find().sort({name: 1}) // 1 asc
$ db.users.find().sort({age: -1}) // -1 desc
$ db.users.find().sort({name: 1, age: -1})

$ db.users.find().sort({$natural: 1})

$ db.users.find({name: "a"}).explain()
$ db.users.find({name: "a"}).explain("queryPlanner")
$ db.users.find({name: "a"}).explain("executionStats")
$ db.users.find({name: "a"}).explain("allPlansExecution")
$ db.users.find({name: "a"}).explain(true)
$ db.users.find({name: "a"}).explain(false)

$ db.users.group({key: {role: 1}, reduce: function(a, result){ result.sum_age += a.age}, initial:{sum_age: 0}})

$ db.users.find({name: {$regex: /^a/}})
$ db.users.find({name: /a/})

$ db.users.find().limit(1)