// ----------------------------- general -----------------------

db // show current database
show dbs // dhow all databases
use DB_NAME // create or switch to database
show collections // show all collections inside a database
db.runCommand({dropDatabase:1}) // drop current database

// ----------------------------- Find -----------------------

db.test.findOne() // display one randmly
db.test.find() // diplay all
db.test.find({nom:"smith"},{nom:true,age:true}) // first object is like WHERE 2nd is WHAT TO DISPLAY

db.test.find({"age":27}) // select * from test where age=27
db.test.find({},{"nom":1,"age":1}) // select nom,age from test
db.test.find({},{"nom":0}) // select age,profession from test

db.test.find({"age":{"$gte":18,"$lte":30}}) // select * from test where age between 18 and 30
db.test.find({"num":{"$in":[151,254,587]}}) // select * from test where num in (151,254,587)