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

Limiting Results

We know that the SELECT operator can retrieve all rows from a table of all or the specific columns. However, what if we only need to fetch a specific number of rows?

We can do it using the LIMIT clause. It is always used at the end of the query. Here is the syntax for it:

In the example below, we extract the first 7 rows (in our case, the capitals of the countries) from the column:


              123
            
SELECT capital 
FROM country 
LIMIT 7;

Here's a short example of the country table:

Task

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Write an SQL query to retrieve 3 distinct continent values from the country table.

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 1. Chapter 5

Limiting Results

We know that the SELECT operator can retrieve all rows from a table of all or the specific columns. However, what if we only need to fetch a specific number of rows?

We can do it using the LIMIT clause. It is always used at the end of the query. Here is the syntax for it:

In the example below, we extract the first 7 rows (in our case, the capitals of the countries) from the column:


              123
            
SELECT capital 
FROM country 
LIMIT 7;

Here's a short example of the country table:

Task

Swipe to show code editor

Write an SQL query to retrieve 3 distinct continent values from the country table.

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 1. Chapter 5

Limiting Results

We know that the SELECT operator can retrieve all rows from a table of all or the specific columns. However, what if we only need to fetch a specific number of rows?

We can do it using the LIMIT clause. It is always used at the end of the query. Here is the syntax for it:

In the example below, we extract the first 7 rows (in our case, the capitals of the countries) from the column:


              123
            
SELECT capital 
FROM country 
LIMIT 7;

Here's a short example of the country table:

Task

Swipe to show code editor

Write an SQL query to retrieve 3 distinct continent values from the country table.

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

Everything was clear?

Thanks for your feedback!

We know that the SELECT operator can retrieve all rows from a table of all or the specific columns. However, what if we only need to fetch a specific number of rows?

We can do it using the LIMIT clause. It is always used at the end of the query. Here is the syntax for it:

In the example below, we extract the first 7 rows (in our case, the capitals of the countries) from the column:


              123
            
SELECT capital 
FROM country 
LIMIT 7;

Here's a short example of the country table:

Task

Swipe to show code editor

Write an SQL query to retrieve 3 distinct continent values from the country table.

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

Section 1. Chapter 5

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