Procedures

Procedures are blocks of SQL code that are saved in a database and can be executed repeatedly on demand. Also referred to as stored procedures — they can be defined with parameters to be used within the body of the procedure, produce an output value, or both.

The syntax for creating a procedure varies depending upon the type of database management system (DBMS) being used. Below is an example procedure defined and executed with MySQL that accepts two parameters and returns an output value.

MySQL Example

# Set the default delimiter so the procedure can include semicolons
DELIMITER //

# Create the procedure
CREATE PROCEDURE add_int (IN x INT, IN y INT, OUT z INT)
BEGIN
  SELECT x + y INTO z;
END //

# Set the delimiter back to the default
DELIMITER ;

# Execute the stored procedure
CALL add_int (5, 3, @z);
# Return the output parameter
SELECT @z AS Result;