Boolean type behavior in PostgreSQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select all rows where the boolean column is true.

PostgreSQL

SELECT * FROM users WHERE active = [1];

Drag options to blanks, or click blank then click option'

A1

B'true'

CTRUE

D't'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'true' as a string instead of the boolean literal TRUE.

Using 1 which is not a boolean literal in PostgreSQL.

In PostgreSQL, the boolean literal TRUE is used without quotes to represent true values.

2fill in blank

medium

Complete the code to insert a false boolean value into the column.

PostgreSQL

INSERT INTO settings (enabled) VALUES ([1]);

Drag options to blanks, or click blank then click option'

AFALSE

B'f'

C0

D'false'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'false' as a string instead of the boolean literal FALSE.

Using 0 which is not a boolean literal in PostgreSQL.

Use the boolean literal FALSE without quotes to insert a false value in PostgreSQL.

3fill in blank

hard

Fix the error in the WHERE clause to correctly filter rows where the boolean column is not true.

PostgreSQL

SELECT * FROM tasks WHERE completed [1] TRUE;

Drag options to blanks, or click blank then click option'

A!=

B<>

C=!

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' which is not standard SQL in PostgreSQL.

Using '==' which is invalid in SQL.

In SQL, the standard operator for 'not equal' is <>.

4fill in blank

hard

Fill both blanks to create a query that selects rows where the boolean column is true or null.

PostgreSQL

SELECT * FROM orders WHERE status = [1] OR status IS [2];

Drag options to blanks, or click blank then click option'

ATRUE

BFALSE

CNULL

DNOT NULL

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'FALSE' instead of TRUE.

Using IS NOT NULL instead of IS NULL.

To check for true or null values, use TRUE and IS NULL respectively.

5fill in blank

hard

Fill all three blanks to create a query that counts rows where the boolean column is false and not null.

PostgreSQL

SELECT COUNT(*) FROM logs WHERE flag = [1] AND flag IS NOT [2] AND flag IS NOT [3];

Drag options to blanks, or click blank then click option'

ATRUE

BFALSE

CNULL

DNOT NULL

Attempts:

3 left

💡 Hint

Common Mistakes

Using TRUE instead of FALSE.

Using IS NULL instead of IS NOT NULL.

We count rows where flag is FALSE and not NULL, using IS NOT NULL conditions.