How to Call a Function in MySQL: Syntax and Examples

In MySQL, you call a stored function by using SELECT function_name(arguments); or within SQL statements like WHERE or SET. The function must be created beforehand using CREATE FUNCTION.

Syntax

To call a stored function in MySQL, use the SELECT statement followed by the function name and parentheses enclosing any required arguments.

• function_name: The name of the stored function.
• arguments: Values or columns passed to the function, separated by commas.

Example syntax:

sql

SELECT function_name(argument1, argument2, ...);

Example

This example shows how to create a simple function that adds two numbers and then call it using SELECT.

sql

DELIMITER $$
CREATE FUNCTION add_numbers(a INT, b INT) RETURNS INT
BEGIN
  RETURN a + b;
END$$
DELIMITER ;

SELECT add_numbers(5, 3) AS result;

Output

result
8

Common Pitfalls

Common mistakes when calling functions in MySQL include:

• Not creating the function before calling it.
• Using parentheses incorrectly or missing arguments.
• Trying to call a procedure like a function (procedures use CALL instead).
• Calling functions in contexts where they are not allowed, like inside some DDL statements.

Example of wrong and right calls:

sql

-- Wrong: calling a procedure like a function
-- SELECT my_procedure(); -- This will cause an error
-- CALL my_procedure();

-- Right: calling a function
SELECT add_numbers(2, 4);

Quick Reference

Action	Syntax Example	Notes
Create Function	CREATE FUNCTION name(params) RETURNS type BEGIN ... END;	Define reusable logic
Call Function	SELECT name(args);	Use in queries or expressions
Call Procedure	CALL procedure_name(args);	Different from functions
Check Functions	SHOW FUNCTION STATUS;	List all functions in database

Key Takeaways

Call MySQL functions using SELECT with the function name and arguments in parentheses.

Functions must be created first using CREATE FUNCTION before calling.

Do not confuse functions with procedures; procedures use CALL, functions use SELECT.

Always provide the correct number and type of arguments when calling a function.

Use SHOW FUNCTION STATUS to see available functions in your database.