FIND Tutorial

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Working with the world collection of countries

This tutorial introduces NoSQL using MongoDB. We will be using the find() command and comparison functions on the collection world which contains details of around 250 countries of the world:

FIND examples are available.

Show Germany

Use find() to show the details of Germany

Show Germany instead of France

db.world.find({name:'France'})

db.world.find({name:'Germany'})

Eurasia

You can use .pretty() to make the output more readable.

List all the countries in the continent of "Eurasia"

db.world.find({name:'Germany'}).pretty()

db.world.find({continent:"Eurasia"}).pretty()

Find an area

You can test numbers as well as strings

Find the country with an area of exactly 43094

db.world.find({gdp:3425956000000}).pretty()

db.world.find({area:43094}).pretty()

Using $gt

You can use $gt and $lt to compare numbers and strings ($gt is greater than, $lt is less than)

Show each country with a population of over 250000000

db.world.find(
    {area:{$gt:9000000}},
    {name:1,_id:0}
).pretty()

db.world.find({population:{$gt:250000000}},{name:1,_id:0}).pretty()

After S

List the countries that come after "S" in the alphabet


db.world.find(

   {name:{$gt:"S"}},
   {name:1,_id:0}

).pretty()

Name and Capital

Find the name and capital cities for countries with a population of over 70 million


db.world.find(

   {population:{$gt:70000000}},
   {name:1,capital:1,_id:0}

).pretty()

Using $or

Find the countries that have a population of over 200 million or less than 20,000

db.world.find({$or:[{name:'Germany'},
                    {name:'France'}]},
              {name:1,population:1,_id:0})

db.world.find({$or:[{population:{$gt:200000000}},

                   {population:{$lt:20000     }}]},
             {name:1,population:1,_id:0})