Difference between revisions of "FIND Tutorial"
From NoSQLZoo
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| Line 12: | Line 12: | ||
Show Germany instead of France. | Show Germany instead of France. | ||
</p> | </p> | ||
| − | <pre class="def"><nowiki>db.world.find({name:'France'})</nowiki></pre> | + | <pre class="def"><nowiki>db.world.find({name:'France'});</nowiki></pre> |
| − | <pre class="ans"><nowiki>db.world.find({name:'Germany'})</nowiki></pre> | + | <pre class="ans"><nowiki>db.world.find({name:'Germany'});</nowiki></pre> |
</div> | </div> | ||
==Eurasia== | ==Eurasia== | ||
| Line 21: | Line 21: | ||
List all the countries in the continent of "Eurasia". | List all the countries in the continent of "Eurasia". | ||
</p> | </p> | ||
| − | <pre class="def"><nowiki>db.world.find({name:'Germany'}).pretty()</nowiki></pre> | + | <pre class="def"><nowiki>db.world.find({name:'Germany'}).pretty();</nowiki></pre> |
| − | <pre class="ans"><nowiki>db.world.find({continent:"Eurasia"}).pretty()</nowiki></pre> | + | <pre class="ans"><nowiki>db.world.find({continent:"Eurasia"}).pretty();</nowiki></pre> |
</div> | </div> | ||
==Find an area== | ==Find an area== | ||
| Line 30: | Line 30: | ||
Find the country with an area of exactly 43094. | Find the country with an area of exactly 43094. | ||
</p> | </p> | ||
| − | <pre class="def"><nowiki>db.world.find({gdp:3425956000000}).pretty()</nowiki></pre> | + | <pre class="def"><nowiki>db.world.find({gdp:3425956000000}).pretty();</nowiki></pre> |
| − | <pre class="ans"><nowiki>db.world.find({area:43094}).pretty()</nowiki></pre> | + | <pre class="ans"><nowiki>db.world.find({area:43094}).pretty();</nowiki></pre> |
</div> | </div> | ||
| Line 43: | Line 43: | ||
<pre class="def"><nowiki> | <pre class="def"><nowiki> | ||
db.world.find( | db.world.find( | ||
| − | {area:{$gt:9000000}}, | + | {area: {$gt: 9000000}}, |
| − | {name:1,_id:0} | + | {name: 1, _id: 0} |
).sort( | ).sort( | ||
{name: 1} | {name: 1} | ||
| − | ).pretty() | + | ).pretty(); |
</nowiki></pre> | </nowiki></pre> | ||
<pre class="ans"><nowiki> | <pre class="ans"><nowiki> | ||
| − | db.world.find({population:{$gt:250000000}},{name:1,_id:0}).sort({name: 1}).pretty() | + | db.world.find({population:{$gt:250000000}},{name:1,_id:0}).sort({name: 1}).pretty(); |
</nowiki></pre> | </nowiki></pre> | ||
</div> | </div> | ||
| Line 58: | Line 58: | ||
List the countries that come after "S" in the alphabet. | List the countries that come after "S" in the alphabet. | ||
</p> | </p> | ||
| − | <pre class="def"><nowiki>db.world.findOne()</nowiki></pre> | + | <pre class="def"><nowiki>db.world.findOne();</nowiki></pre> |
| − | <pre class="ans"><nowiki> | + | <pre class="ans"><nowiki>db.world.find(name:{$gt:"S"}},{name:1,_id:0}).pretty();</nowiki></pre> |
| − | db.world.find( | ||
| − | |||
| − | |||
| − | ).pretty() | ||
| − | |||
</div> | </div> | ||
==Name and Capital== | ==Name and Capital== | ||
| Line 71: | Line 66: | ||
Find the name and capital cities for countries with a population of over 70 million. | Find the name and capital cities for countries with a population of over 70 million. | ||
</p> | </p> | ||
| − | <pre class="def"><nowiki>db.world.findOne()</nowiki></pre> | + | <pre class="def"><nowiki>db.world.findOne();</nowiki></pre> |
| − | <pre class="ans"><nowiki> | + | <pre class="ans"><nowiki>db.world.find({population:{$gt:70000000}},{name:1,capital:1,_id:0}).pretty();</nowiki></pre> |
| − | db.world.find( | ||
| − | |||
| − | |||
| − | ).pretty() | ||
| − | |||
</div> | </div> | ||
| Line 87: | Line 77: | ||
<pre class="def"><nowiki> | <pre class="def"><nowiki> | ||
db.world.find( | db.world.find( | ||
| − | {$or:[ | + | {$or: [ |
{name:'Germany'}, | {name:'Germany'}, | ||
{name:'France'} | {name:'France'} | ||
]}, | ]}, | ||
| − | {name:1, population:1, _id:0} | + | {name: 1, population: 1, _id: 0} |
| − | ) | + | ); |
</nowiki></pre> | </nowiki></pre> | ||
<pre class="ans"><nowiki>db.world.find({$or:[{population:{$gt:200000000}},{population:{$lt:20000}}]},{name:1,population:1,_id:0})</nowiki></pre> | <pre class="ans"><nowiki>db.world.find({$or:[{population:{$gt:200000000}},{population:{$lt:20000}}]},{name:1,population:1,_id:0})</nowiki></pre> | ||
</div> | </div> | ||
Revision as of 19:59, 21 June 2018
Contents
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 (greater than) and $lt (less than) to compare numbers and strings.
Show each country with a population of over 250000000
Sort the results alphabetically.
db.world.find(
{area: {$gt: 9000000}},
{name: 1, _id: 0}
).sort(
{name: 1}
).pretty();
db.world.find({population:{$gt:250000000}},{name:1,_id:0}).sort({name: 1}).pretty();
After S
List the countries that come after "S" in the alphabet.
db.world.findOne();
db.world.find(name:{$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.findOne();
db.world.find({population:{$gt:70000000}},{name:1,capital:1,_id:0}).pretty();
Using $or
Find the countries that have a population that is over 200 million or less than 20,000.
db.world.find(
{$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})