IF function in MySQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the IF function do in MySQL?

The IF function checks a condition and returns one value if the condition is true, and another value if it is false.

beginner

Write the syntax of the IF function in MySQL.

IF(condition, value_if_true, value_if_false)

intermediate

How does the IF function differ from the CASE statement in MySQL?

IF is used for simple two-way decisions (true/false), while CASE can handle multiple conditions and outcomes.

beginner

Example: What will this query return? SELECT IF(5 > 3, 'Yes', 'No');

It will return 'Yes' because 5 is greater than 3, so the condition is true.

intermediate

Can the IF function be nested inside another IF function in MySQL?

Yes, you can nest IF functions to check multiple conditions step-by-step.

What will this MySQL query return? SELECT IF(10 = 10, 'Equal', 'Not Equal');

A NULL

B 'Not Equal'

C 'Equal'

D Error

The condition 10 = 10 is true, so IF returns 'Equal'.

Which part of IF(condition, value_if_true, value_if_false) is evaluated first?

A All at once

B value_if_true

C value_if_false

D condition

The condition is evaluated first to decide which value to return.

Can IF function return NULL as a value_if_true or value_if_false?

A Yes

B No

C Only value_if_true can be NULL

D Only value_if_false can be NULL

IF can return NULL for either true or false results.

Which of these is a valid use of IF in MySQL?

A SELECT IF age >= 18, 'Adult', 'Minor' FROM users;

B SELECT IF(age >= 18, 'Adult', 'Minor') FROM users;

C SELECT IF(age >= 18 THEN 'Adult' ELSE 'Minor') FROM users;

D SELECT IF(age >= 18 'Adult', 'Minor') FROM users;

Option B uses correct IF syntax with condition and two values.

What happens if the condition in IF is NULL?

A IF returns value_if_false

B IF returns value_if_true

C IF returns NULL

D IF throws an error

If condition is NULL, it is treated as false, so IF returns value_if_false.

Explain how the IF function works in MySQL and give a simple example.

Think about a question with two possible answers.

Describe a situation where nesting IF functions would be useful in a database query.

Imagine checking age groups or multiple categories.