MySQL觸發器-引用語句

Question

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

產生以下錯誤：

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

為什么是這樣？

Answer 1

如果要查看舊表，則應創建BEFORE DELETE觸發器-

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