我正在尝试创建一个触发器,它将根据用户输入的lat / lng列更新GEOMETRY列.我的触发器看起来像这样 –

CREATE TRIGGER `tbl.foo`   
    AFTER INSERT ON `tbl` FOR EACH ROW  
    BEGIN  
        UPDATE tbl
        SET coord = Point(lng, lat)
        WHERE id = NEW.id; 
    END

但是,当我插入一个带有lng,lat值的新行时,我收到以下错误 –

ERROR 1442 (HY000): Can’t update table ‘tbl’ in stored function/trigger because it is already used by statement which invoked this stored function/trigger.

我可以不创建这样的触发器吗？如果没有,自动化的方法是什么？

解决方法:

尝试使用BEFORE INSERT触发器并修改所需的值,例如 –

CREATE TRIGGER trigger1
  BEFORE INSERT
  ON table1
  FOR EACH ROW
BEGIN
  SET NEW.column1 = 'another value';
END

编辑

CREATE TABLE table_test_trigger (
  id INT(11) NOT NULL AUTO_INCREMENT,
  a INT(11) DEFAULT NULL,
  b INT(11) DEFAULT NULL,
  c INT(11) DEFAULT NULL,
  PRIMARY KEY (id)
);

DELIMITER $$

CREATE TRIGGER trigger1
    BEFORE INSERT
    ON table_test_trigger
    FOR EACH ROW
BEGIN
  SET NEW.c = NEW.a + NEW.b;
END
$$

DELIMITER ;

INSERT INTO table_test_trigger(a, b) VALUES (10, 5);

SELECT * FROM table_test_trigger;

+----+------+------+------+
| id | a    | b    | c    |
+----+------+------+------+
|  1 |   10 |    5 |   15 |
+----+------+------+------+