Declaring variables in PLSQL triggers in mysql - mysql

Question

I am writing PLSQL trigger for MySQL database. I am trying to declare variables . So i am writing a declare block in the trigger. Here is my following code
CREATE TRIGGER leave_approve_trigger
AFTER UPDATE ON leave_status
FOR EACH ROW
DECLARE //Syntax error
current_id integer;
BEGIN
if NEW.status == 'APPROVED'
THEN
select id into current_id from leave_request_table;
insert into update_table values(current_id);
ENDIF;
END;
The error I get is syntax error for mysql version 5.5.0. Can we actually declare variables. Thanks in advance

Answer 1

The procedure syntax in a little different in MySQL, you must change some lines:
Declare block must be after begin of code.
the == operator but chanted to =
ENDIF; must change to END IF;
All block must begin with changing the delimiter for statements, and at the end restore it.
If a field name is a reserved word it can be enclosed by ` to avoid syntax error.
Here is the code:
DELIMITER $$
CREATE TRIGGER leave_approve_trigger
AFTER UPDATE ON leave_status
FOR EACH ROW
BEGIN
DECLARE current_id int;
if NEW.`status` = 'APPROVED' THEN
select id into current_id from leave_request_table;
insert into update_table values(current_id);
END IF;
END$$
DELIMITER ;

Answer 2

I think the MySQL version would be more like this:
delimiter $$
CREATE TRIGGER leave_approve_trigger AFTER UPDATE ON leave_status
FOR EACH ROW
BEGIN
if NEW.status = 'APPROVED' THEN
insert into update_table
select id
from leave_request_table;
END IF;
END;
delimiter ;
By the way, you don't need the variable in either Oracle or MySQL. Just use insert . . . select.
I would think that you would also want to match to a specific row in the leave_request_table, but your trigger doesn't do that.