Triggers and stored proc in MySQL - mysql

Question

I used MSSQL stored procedures and triggers for a while; MySQL is getting me absolutely crazy about how to write even the simpler procedure.
Why I get a syntax error in this so stuoid trigger?
CREATE TRIGGER set_prio_default BEFORE INSERT ON categories
FOR EACH ROW
BEGIN
set #my_prio := 1;
SET new.prio := #my_prio;
END
In facts this TRIGGER is an oversemplification of:
DELIMITER $$
DROP PROCEDURE IF EXISTS `slot08`.`test` $$
CREATE PROCEDURE `slot08`.`test` ()
BEGIN
select 1 + max(prio) from categories INTO #my_prio;
select #my_prio;
END $$
DELIMITER ;
Still i do not understand how to use variables in procedures. If I use a DECLARE statement and the variable name miss the # character I got an error from mysql telling me "unknown system variable" - but many examples I saw used this syntax
I mean:
this does not work
CREATE TRIGGER set_prio_default BEFORE INSERT ON categories
FOR EACH ROW
BEGIN
declare my_prio integer default 1;
set my_prio := 1;
SET new.prio := my_prio;
END
If I use # I get syntax error.
Have some hints?
Thanks!

Answer 1

I dont think you have to use the := operator. A simple equals will do. All variables declared inside the stored procedure must be prefixed with the #symbol.

Answer 2

Hey, found the answer. Hope that people with so little experience as me in MySQL procedures could avoid to spend the time I have spent on the same issue. This does work:
DELIMITER $$
CREATE TRIGGER blablabla
BEFORE INSERT ON myStupidTable
FOR EACH ROW
BEGIN
declare my_prio integer;
select 1 + max(prio) from myStupidTable INTO my_prio;
SET new.prio := my_prio;
END $$
DELIMITER ;
It seems that the MySQL syntax errors experienced so far were a delimiter issue.
Greetings
Daniel