Question

如果您习惯使用MySQL，我的问题对您来说可能很简单。我已经习惯了PostgreSQL SGBD，我正在尝试将PL / PgSQL脚本翻译成MySQL。

这就是我所拥有的：

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//

但MySQL Workbench在DECLARE m_projects_id上给出了错误。我真的不明白，因为我上面有两行相同的指令...

任何提示？

编辑：neubert解决了这个错误。谢谢。

但是，当我尝试插入用户时：

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

你知道吗？或者更好，你知道我怎么能得到更好的错误信息吗？

Answer 1

所有DECLARE都需要位于顶部。即

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//

Answer 2

同意关于DECLARE语句的neubert，这将修复语法错误。但我建议你避免使用开放游标，它们可能会很慢。

对于您的任务：使用INSERT ... SELECT语句，它将帮助您仅使用一个查询将数据从一个表复制到另一个表。

INSERT ... SELECT Syntax

声明变量MySQL触发器

2 个答案: