CODEWITHSUNDEEP
mysqlsqlstored-procedurestriggers
Arthur
Arthur

Reputation: 3807

Declare variable MySQL trigger

My question might be simple for you, if you're used to MySQL. I'm used to PostgreSQL SGBD and I'm trying to translate a PL/PgSQL script to MySQL.

Here is what I have :

delimiter //

CREATE TRIGGER pgl_new_user 
AFTER INSERT ON users FOR EACH ROW
BEGIN
    DECLARE m_user_team_id integer;
    SELECT id INTO m_user_team_id FROM user_teams WHERE name = "pgl_reporters";

    DECLARE m_projects_id integer;
    DECLARE cur CURSOR FOR SELECT project_id FROM user_team_project_relationships WHERE user_team_id = m_user_team_id;

    OPEN cur;
        ins_loop: LOOP
            FETCH cur INTO m_projects_id;
            IF done THEN
                LEAVE ins_loop;
            END IF;
            INSERT INTO users_projects (user_id, project_id, created_at, updated_at, project_access) 
            VALUES (NEW.id, m_projects_id, now(), now(), 20);
        END LOOP;
    CLOSE cur;
END//

But MySQL Workbench gives me an error on DECLARE m_projects_id. I don't really understand because I've the same instruction two lines above...

Any hints ?

EDIT: neubert solved this error. Thanks.

But yet, when I try to insert into users : 

Error Code: 1329. No data - zero rows fetched, selected, or processed

Do you have any idea ? Or better, do you know how I can get a better error message ?

Upvotes: 26

Views: 171958

Answers (2)

amk
amk

Reputation: 282

Agree with neubert about the DECLARE statements, this will fix syntax error. But I would suggest you to avoid using openning cursors, they may be slow.

For your task: use INSERT...SELECT statement which will help you to copy data from one table to another using only one query.

INSERT ... SELECT Syntax.

Upvotes: 0

neubert
neubert

Reputation: 16792

All DECLAREs need to be at the top. ie.

delimiter //

CREATE TRIGGER pgl_new_user 
AFTER INSERT ON users FOR EACH ROW
BEGIN
    DECLARE m_user_team_id integer;
    DECLARE m_projects_id integer;
    DECLARE cur CURSOR FOR SELECT project_id FROM user_team_project_relationships WHERE user_team_id = m_user_team_id;

    SET @m_user_team_id := (SELECT id FROM user_teams WHERE name = "pgl_reporters");

    OPEN cur;
        ins_loop: LOOP
            FETCH cur INTO m_projects_id;
            IF done THEN
                LEAVE ins_loop;
            END IF;
            INSERT INTO users_projects (user_id, project_id, created_at, updated_at, project_access) 
            VALUES (NEW.id, m_projects_id, now(), now(), 20);
        END LOOP;
    CLOSE cur;
END//

Upvotes: 45

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