Course Content

Introduction to SQL

1. Retrieving Data

Retrieving Individual Columns Retrieving Multiple Columns Retrieving All Columns Retrieving Distinct Rows Limiting Results Challenge: Find the Population of the Countries Challenge: Find All Countries Challenge: Find All Countries With Their IDs Challenge: Find Country Capitals Challenge: Find the Regions in Which All Countries Are Located

2. Sorting Retrieved Data

Sorting Data Challenge: Population Sort Sorting by Multiple Columns Challenge: Dual-Sort Query Specifying Sort Direction Challenge: Sort the Countries by Region and Capital Challenge: Sort Capitals in Descending Order Challenge: Sort Countries in Ascending Order Challenge: Find Countries, Their IDs, and Their Populations Challenge: Find Countries, IDs, Populations, Regions, and Sort Them Challenge: Find All Continents and Sort Them in Ascending Order

3. Filtering Data

Using the WHERE Clause Challenge: North America Population Sort The WHERE Clause Operators Challenge: Population Threshold Query Checking for a Range of Values Checking for NO Value

4. Advanced Data Filtering

Using the AND Operator Challenge: Europe Region Sort Using the OR operator Challenge: America Regions Filter Using the NOT Operator Challenge: Non-Europe Capitals Sort

5. Aggregate Functions

The AVG() Function Challenge: Surface Area Selection The COUNT() Function Challenge: Continental Count The MAX() Function The MIN() Function Challenge: Large Surface Area Average The SUM() Function

The WHERE Clause Operators

SQL supports a lot of conditional statements.

Less Than

Let’s look at the examples:
This example lists all countries that have a population of less than 2424200:


              123
            
SELECT name, population
FROM country
WHERE population < 2424200;

Less Than or Equal to

The following example retrieves all countries with a population less than or equal to 2424200:


              123
            
SELECT name, population
FROM country
WHERE population <= 2424200;

Not Equal

The following example retrieves all non-Asian countries:


              123
            
SELECT name, continent
FROM country
WHERE continent<>'Asia';

Here is the country table we are working with:

Task

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Write an SQL query to retrieve the name, population, region, and capital columns from the country table (please retrieve these columns in this order), returning only the countries with a region named Southern Europe.

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Section 3. Chapter 3

The WHERE Clause Operators

SQL supports a lot of conditional statements.

Less Than

Let’s look at the examples:
This example lists all countries that have a population of less than 2424200:


              123
            
SELECT name, population
FROM country
WHERE population < 2424200;

Less Than or Equal to

The following example retrieves all countries with a population less than or equal to 2424200:


              123
            
SELECT name, population
FROM country
WHERE population <= 2424200;

Not Equal

The following example retrieves all non-Asian countries:


              123
            
SELECT name, continent
FROM country
WHERE continent<>'Asia';

Here is the country table we are working with:

Task

Swipe to show code editor

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 3. Chapter 3

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