MySql触发器-引用语句

产生以下错误：

CREATE TRIGGER Tr1
AFTER DELETE ON Table1
REFERENCING
    OLD TABLE AS OldTable,
    NEW TABLE AS NewTable
FOR EACH STATEMENT

---

这是为什么？

如果要查看旧表，则应在删除触发器之前创建-

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that     corresponds to your MySQL server version for the right syntax to use near 'REFERENCING 
OLD TABLE AS OldTable,
NEW TABLE AS NewTable

---

请参阅

引用

不是MySQL的一部分。因此，如果我想执行类似于此处的操作，如何引用旧表，即其状态

CREATE TRIGGER Tr1
  BEFORE DELETE
  ON Table1
  FOR EACH ROW
BEGIN
  ...
  SET @old_count = NULL;
  SELECT COUNT(*) INTO @old_count FROM Table1;
  ...
END