Mysql Stored Function Parameter

I have just started to create a stored function this is my first time so I am having a few problems. Currently I call the function using SELECT test(); (test is the function name f

Solution 1:

Use:

DROPFUNCTION IF EXISTS `example`.`test` $$
CREATEFUNCTION `example`.`test` (param INT) RETURNSVARCHAR(32)
BEGINDECLARE new_username VARCHAR(32);

    SELECT `username`
      INTO new_username
      FROM `users`
     WHERE `ID` = param;

    RETURNCOALESCE(new_username, 'Username not found');

END $$

Mind that the VARCHAR length of the RETURN value matches the variable, which should match the column length you want to return.