Question

Tab_1

"id"    "name"      "addr"  "country"   "status"
"1"     "norman"    "1st"   "US"        "2"
"2"     "kirk"      "2nd"   "US"        "2"

Tab_2

"id"    "name"      "addr"  "country"   "pos"   "total"
"1"     "norman"    "1st"   "US"        "0"     "0"
"2"     "kirk"      "2nd"   "US"        "0"     "0"

当update中的状态设置为Tab_1时update Tab_2 Tab_1 0 CREATE DEFINER=`root`@`localhost` TRIGGER `tab_2_upd` AFTER UPDATE ON `tab_1` FOR EACH ROW BEGIN if new.status = '0' then update tab_2 set pos = pos+1, total = total+1 where id = new.id; //Should it be new.id or old.id? I tried both but still no luck. end if; END后{}}} 。问题是，即使它是正确的，它也什么都不做。我该如何设置呢？

{{1}}

Answer 1

这是因为您没有更改分隔符而导致多个语句被破坏的另一种情况。这是一个非常常见的错误。

试试这个：

DELIMITER $$

DROP TRIGGER IF EXISTS  `tab_2_upd`$$

CREATE DEFINER=`root`@`localhost` TRIGGER `tab_2_upd` AFTER UPDATE ON `tab_1` 
FOR EACH ROW BEGIN
    if new.status = '0' then
        update tab_2 set pos = pos+1, total = total+1 where id = new.id;
    end if;
END$$

DELIMITER ;

ON UPDATE触发器同时具有OLD和NEW值，并且因为我认为id的值不会改变（它不应该），所以使用任何值都是安全的（OLD或NEW））。

对分隔符here有一个很好的答案。

即使一切正确，更新后的MySql触发器也不会更新

1 个答案: