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 Sorting by Multiple Columns Challenge 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 The WHERE Clause Operators Challenge Checking for a Range of Values Checking for NO Value

4. Advanced Data Filtering

Using the AND Operator Challenge Using the OR operator Challenge Using the NOT Operator Challenge

5. Aggregate Functions

The AVG() Function Challenge The COUNT() Function Challenge The MAX() Function The MIN() Function Challenge The SUM() Function

Introduction to SQL

The WHERE Clause Operators

SQL supports a lot of conditional statements.

Operator	Equality
=	Equality
<>	Inequality
<	Less than
<=	Less than or equal to
>	Greater than
>=	Greater than or equal to
BETWEEN	Between two specified values
IS NULL	Is a NULL value

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

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

The following example retrieves all non-Asian countries:

Task

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.

Please note that Southern Europe should be correctly capitalized, and southern europe is not the same. So, be careful and write it as Southern Europe.

Here's a short example of the country table:

id	name	continent	region	surfacearea	capital	population
1	Japan	Asia	Eastern Asia	377829	Tokyo	126714000
2	Latvia	Europe	NULL	64589	Riga	2424200
3	Mexico	North America	Central America	1958201	Mexico City	98881000
...	...	...	...	...	...	...
15	Malta	Europe	Southern Europe	316	Valletta	380200

Everything was clear?

Section 3. Chapter 3