WHERE with IS NULL and IS NOT NULL in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select rows where the column 'email' has no value (is NULL).

SQL

SELECT * FROM users WHERE email [1] NULL;

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

ALIKE

B=

CIS

DNOT

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' instead of 'IS' to check for NULL.

Using 'LIKE' which is for pattern matching, not NULL checks.

In SQL, to check if a column is NULL, you use IS NULL. Using '=' does not work for NULL values.

2fill in blank

medium

Complete the code to select rows where the column 'phone' has a value (is NOT NULL).

SQL

SELECT * FROM contacts WHERE phone [1] NOT NULL;

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

AIS

B=

CLIKE

DNOT LIKE

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' or 'LIKE' instead of 'IS' for NULL checks.

Forgetting to include 'NOT' before NULL.

To check for values that are not NULL, use IS NOT NULL in SQL.

3fill in blank

hard

Fix the error in the code to select rows where 'address' is NULL.

SQL

SELECT * FROM customers WHERE address [1] NULL;

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

AIS

B!=

C<>

DLIKE

Attempts:

3 left

💡 Hint

Common Mistakes

Using '= NULL' which always returns false.

Using '!=' or '<>' to check for NULL.

Using '=' to compare with NULL is incorrect. Use IS NULL to check for NULL values.

4fill in blank

hard

Fill both blanks to select rows where 'status' is NOT NULL and 'email' is NULL.

SQL

SELECT * FROM users WHERE status [1] NOT NULL AND email [2] NULL;

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

AIS

B=

CIS NOT

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' or '!=' instead of 'IS' for NULL checks.

Mixing up NULL and NOT NULL syntax.

Use IS NOT NULL to check for values present and IS NULL to check for missing values.

5fill in blank

hard

Fill all three blanks to select rows where 'last_login' is NOT NULL, 'email' is NOT NULL, and 'phone' is NULL.

SQL

SELECT * FROM members WHERE last_login [1] NOT NULL AND email [2] NOT NULL AND phone [3] NULL;

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

AIS

BIS NOT

C=

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' or '!=' instead of 'IS' or 'IS NOT'.

Confusing NULL and NOT NULL syntax.

Use IS NOT NULL to check for values present and IS NULL to check for missing values in SQL.