use shopping
db
show dbs 
use shopping1
show dbs
db.dropDatabase()
show dbs
use shopping 
show dbs
use shopping 
show collections
db.product.find().limit(2)
db.product.find().limit(1)
db.product.find().sort({key:1})
db.product.find({},{"productname":1,_id:0}).sort({"productname":1})
db.product.find({},{"productname":1,"price":1,_id:0}).sort({"price":-1})
db.product.find({},{"productname":1,"stockquantity":1,_id:0}).sort({"stockquantity":1})
db.product.find({},{_id:0}).limit(3).sort({"stockquantity":1})
db.product.find({},{"category":1,_id:0}).limit(3).sort({"category":-1})
db.product.find({},{"category":1,_id:0}).limit(5).sort({"category":-1})

db.product.find({"price":{$eq:5000}})
db.product.find({"stockquantity":{$eq:50}})
db.product.find({"stockquantity":{$gte:50}})
db.product.find({"stockquantity":{$t :50}})
db.product.find({"stockquantity":{$te:50}})
db.product.find({"stockquantity":{$ne :50}})