IF function in MySQL - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

Output of IF function with numeric comparison

What is the output of this MySQL query?

SELECT IF(10 > 5, 'Yes', 'No') AS result;

MySQL

SELECT IF(10 > 5, 'Yes', 'No') AS result;

A NULL

B No

C Yes

D Syntax Error

💡 Hint

IF(condition, true_value, false_value) returns true_value if condition is true.

Since 10 is greater than 5, the condition is true, so IF returns 'Yes'.

❓ query_result

intermediate

Using IF function with NULL value

What will this query return?

SELECT IF(NULL, 'True', 'False') AS output;

MySQL

SELECT IF(NULL, 'True', 'False') AS output;

A False

B True

C NULL

D Error

💡 Hint

In MySQL, NULL is treated as false in IF conditions.

Since NULL is treated as false, IF returns the false_value 'False'.

📝 Syntax

advanced

Identify the syntax error in IF function usage

Which option contains a syntax error in using the IF function in MySQL?

A SELECT IF(score >= 60, 'Pass', 'Fail') FROM exams;

B SELECT IF(score >= 60, 'Pass', 'Fail') result FROM exams;

C SELECT IF(score >= 60, 'Pass', 'Fail') AS result FROM exams;

D SELECT IF(score >= 60, 'Pass') FROM exams;

💡 Hint

IF function requires three arguments: condition, true_value, false_value.

Option D misses the third argument, causing a syntax error.

❓ query_result

advanced

Nested IF function output

What is the output of this query?

SELECT IF(score >= 90, 'A', IF(score >= 75, 'B', 'C')) AS grade FROM (SELECT 80 AS score) AS t;

MySQL

SELECT IF(score >= 90, 'A', IF(score >= 75, 'B', 'C')) AS grade FROM (SELECT 80 AS score) AS t;

A A

B B

C C

D NULL

💡 Hint

Check the score against each condition in order.

Score 80 is not >= 90, so first IF returns false and evaluates second IF. 80 >= 75 is true, so 'B' is returned.

🧠 Conceptual

expert

Behavior of IF function with non-boolean expressions

Consider this query:

SELECT IF('abc', 'Yes', 'No') AS result;

What will be the output and why?

MySQL

SELECT IF('abc', 'Yes', 'No') AS result;

A Yes, because non-empty strings are treated as TRUE in IF condition

B No, because IF only accepts boolean TRUE or FALSE

C NULL, because 'abc' is not a boolean

D Syntax Error, because string literals cannot be used as condition

💡 Hint

In MySQL, non-zero and non-empty values are TRUE in boolean context.

MySQL treats any non-empty string as TRUE in IF condition, so it returns 'Yes'.