Mysql Trigger: Result consisted of more than one row - mysql

Question

I have 3 tables:
Module:
id_module | name
--------------------
1 users
2 roles
...
Profile:
id_profile | name
--------------------
1 admin
2 promoter
And Permission
id | id_profile | id_module | read | write | modify | delete
---------------------------------------------------------------
What I want is a trigger is to fill the table permission every time I insert a new module ... but for every existing profile.
Thus:
INSERT INTO `module` (`name`) VALUES
('user'),
('roles');
Existing profiles admin and promoter permission table would be filled this way:
id | id_profile | id_module | read | write | modify | delete
---------------------------------------------------------------
1 1 1 0 0 0 0
2 1 2 0 0 0 0
3 2 1 0 0 0 0
4 2 2 0 0 0 0
For this, I created the following trigger:
CREATE TRIGGER `create_permission` AFTER INSERT ON `module`
FOR EACH ROW
BEGIN
DECLARE `my_profile` INT(11) ;
SELECT id_profile INTO `my_profile` FROM profile WHERE state <>3;
INSERT INTO `permission` (`id_profile`, `id_module`, `read`, `write`, `modify`, `delete`) VALUES(`my_profile`, NEW.`id_module `,0,0,0,0);
END;
It works well when there is a profile ... when more than one when I return "Result consisted of more than one row"
I read that this problem arises when you declare a variable that supports a single value... You can insert records for each id of the table profile?

Answer 1

As you found out, you may only assign scalar values to a variable.
To iterate over the many results of a SELECT query, you need to use a CURSOR.
I personnaly dislike the cumbersome CURSOR syntax. In your particular case, I would advise the much simpler INSERT INTO...SELECT trick:
INSERT INTO permission (id_profile, id_module, read, write, modify, delete)
SELECT id_profile, NEW.id_module,0,0,0,0 FROM profile WHERE state <> 3;