我想用动态SQL创建一个触发器，我从变量中获取一个列名 . 这是我简化的mysql架构：

CREATE TABLE products (id int);
INSERT INTO products VALUES (1),(2);

CREATE TABLE attribute_values 
(product_id int, `key` varchar(100), value varchar(100));
INSERT INTO attribute_values VALUES
( 1, 'title', 'Orange'),
( 1, 'code', 'O125'),      
( 2, 'title', 'Pizza');


CREATE TABLE product_attributes 
SELECT  products.id,
        MAX(CASE WHEN attribute_values.key = 'title' THEN attribute_values.value END) title,
        MAX(CASE WHEN attribute_values.key = 'code' THEN attribute_values.value END) code
FROM    products JOIN attribute_values ON products.id = attribute_values.product_id
GROUP   BY products.id;


# trigger
DELIMITER //
CREATE PROCEDURE attribute_values_after_insert(IN product_id INT, IN column_name VARCHAR(100), IN val VARCHAR(100))
BEGIN
    SET @sql = NULL;
    SELECT concat('UPDATE product_attributes SET product_attributes.', column_name, '=', val, ' WHERE id=', product_id) INTO @sql;

    PREPARE stmt FROM @sql;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;

    SET @sql = NULL;
END//
DELIMITER ;

DELIMITER //
CREATE TRIGGER attribute_values_insert_trigger AFTER INSERT ON attribute_values FOR EACH ROW
BEGIN
    CALL attribute_values_after_insert(NEW.product_id, NEW.key, NEW.value);
END
DELIMITER ;

http://sqlfiddle.com/#!9/674fd/1

即：

餐桌产品：

+-------------+
| id          |
+-------------+
| 1           |
| 2           |
+-------------+

table attribute_values：

+-------------+----------+-----------+
| product_id  | key      | value     |
+-------------+----------+-----------+
| 1           | title    | Orange    |
| 1           | code     | O125      |
| 2           | title    | Pizza     |
+-------------+----------+-----------+

table product_attributes：

+-------------+----------+-----------+
| id          | title    | code      |
+-------------+----------+-----------+
| 1           | Orange   | 0125      |
| 2           | Pizza    |           |
+-------------+----------+-----------+

在触发器中，我想在插入表attribute_values后更新表product_attributes .

当我执行查询时：

INSERT INTO attribute_values VALUES (2, 'code', '0126');

我收到错误：

MySQL的查询面板中不允许使用DDL和DML语句;只允许SELECT语句 . 将DDL和DML放在架构面板中 .

在mysql中有这个解决方案吗？

谢谢你的努力:)

mysql triggers