mysql - 在 sql 触发器中使用 else if 时出错

Question

我不确定我的代码有什么问题。

 delimiter $$
 CREATE TRIGGER updateRestaurantAtributes 
 AFTER UPDATE ON fields_data
 FOR EACH ROW BEGIN
 IF (NEW.fieldid = 1) THEN
    UPDATE restaurants
    SET address1 = NEW.data_txt 
    Where rid = NEW.itemid;
 ELSE IF (NEW.fieldid = 2) THEN
    UPDATE restaurants
    SET address2 = NEW.data_txt 
    Where rid = NEW.itemid;
 END IF;
END$$

以上版本无效。它说“END”(最后一行)附近有语法错误。但是当我使用时它会起作用

delimiter $$
CREATE TRIGGER updateRestaurantAtributes 
AFTER UPDATE ON fields_data
FOR EACH ROW BEGIN
IF (NEW.fieldid = 1) THEN
    UPDATE restaurants
    SET address1 = NEW.data_txt 
    Where rid = NEW.itemid;
END IF;
IF (NEW.fieldid = 2) THEN
    UPDATE restaurants
    SET address2 = NEW.data_txt 
    Where rid = NEW.itemid;
END IF;
END$$

我不知道为什么。我错过了什么吗？

Answer 1

代替 ELSE IF，MySQL's syntax使用 ELSEIF(没有空格)。

 delimiter $$
 CREATE TRIGGER updateRestaurantAtributes 
 AFTER UPDATE ON fields_data
 FOR EACH ROW BEGIN
 IF (NEW.fieldid = 1) THEN
    UPDATE restaurants
    SET address1 = NEW.data_txt 
    Where rid = NEW.itemid;
 ELSEIF (NEW.fieldid = 2) THEN
    UPDATE restaurants
    SET address2 = NEW.data_txt 
    Where rid = NEW.itemid;
 END IF;
END$$

尽管您可以通过添加额外的 END IF 使其与 ELSE IF 中的空格一起使用。通过使用空格，您可以有效地启动第二个 IF 语句，该语句必须独立于第一个外部 IF 语句关闭。

/* Might work */
delimiter $$
 CREATE TRIGGER updateRestaurantAtributes 
 AFTER UPDATE ON fields_data
 FOR EACH ROW BEGIN
 IF (NEW.fieldid = 1) THEN
    UPDATE restaurants
    SET address1 = NEW.data_txt 
    Where rid = NEW.itemid;
 /* Opens a seconds IF block which must be closed */
 ELSE IF (NEW.fieldid = 2) THEN
    UPDATE restaurants
    SET address2 = NEW.data_txt 
    Where rid = NEW.itemid;
  /* Close inner IF block */
  END IF;
 END IF;
END$$