Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.
Checking for NO Value | Filtering Data
Introduction to SQL
course content

Course Content

Introduction to SQL

Introduction to SQL

1. Retrieving Data
2. Sorting Retrieved Data
3. Filtering Data
4. Advanced Data Filtering
5. Aggregate Functions

bookChecking for NO Value

When a column doesn't have any value, it's regarded as having a NULL value. To identify whether a value is NULL, we check if it's equal to NULL. Alternatively, the SELECT statement provides a WHERE clause and an IS NULL clause, which is used to examine columns with NULL values.

Let's illustrate this with an example:

123
SELECT name FROM country WHERE region IS NULL;
copy

Task

Write an SQL query that returns the name and capital columns with no population.

Here's a short example of the country table:

idnamecontinentregionsurfaceareacapitalpopulation
1JapanAsiaEastern Asia377829Tokyo126714000
2LatviaEuropeNULL64589Riga2424200
3MexicoNorth AmericaCentral America1958201Mexico City98881000
.....................
15MaltaEuropeSouthern Europe316Valletta380200

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 3. Chapter 6
toggle bottom row

bookChecking for NO Value

When a column doesn't have any value, it's regarded as having a NULL value. To identify whether a value is NULL, we check if it's equal to NULL. Alternatively, the SELECT statement provides a WHERE clause and an IS NULL clause, which is used to examine columns with NULL values.

Let's illustrate this with an example:

123
SELECT name FROM country WHERE region IS NULL;
copy

Task

Write an SQL query that returns the name and capital columns with no population.

Here's a short example of the country table:

idnamecontinentregionsurfaceareacapitalpopulation
1JapanAsiaEastern Asia377829Tokyo126714000
2LatviaEuropeNULL64589Riga2424200
3MexicoNorth AmericaCentral America1958201Mexico City98881000
.....................
15MaltaEuropeSouthern Europe316Valletta380200

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

Section 3. Chapter 6
toggle bottom row

bookChecking for NO Value

When a column doesn't have any value, it's regarded as having a NULL value. To identify whether a value is NULL, we check if it's equal to NULL. Alternatively, the SELECT statement provides a WHERE clause and an IS NULL clause, which is used to examine columns with NULL values.

Let's illustrate this with an example:

123
SELECT name FROM country WHERE region IS NULL;
copy

Task

Write an SQL query that returns the name and capital columns with no population.

Here's a short example of the country table:

idnamecontinentregionsurfaceareacapitalpopulation
1JapanAsiaEastern Asia377829Tokyo126714000
2LatviaEuropeNULL64589Riga2424200
3MexicoNorth AmericaCentral America1958201Mexico City98881000
.....................
15MaltaEuropeSouthern Europe316Valletta380200

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Everything was clear?

How can we improve it?

Thanks for your feedback!

When a column doesn't have any value, it's regarded as having a NULL value. To identify whether a value is NULL, we check if it's equal to NULL. Alternatively, the SELECT statement provides a WHERE clause and an IS NULL clause, which is used to examine columns with NULL values.

Let's illustrate this with an example:

123
SELECT name FROM country WHERE region IS NULL;
copy

Task

Write an SQL query that returns the name and capital columns with no population.

Here's a short example of the country table:

idnamecontinentregionsurfaceareacapitalpopulation
1JapanAsiaEastern Asia377829Tokyo126714000
2LatviaEuropeNULL64589Riga2424200
3MexicoNorth AmericaCentral America1958201Mexico City98881000
.....................
15MaltaEuropeSouthern Europe316Valletta380200

Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
Section 3. Chapter 6
Switch to desktopSwitch to desktop for real-world practiceContinue from where you are using one of the options below
some-alt