MySQL foreach替代程序

DECLARE i INT DEFAULT 0;
DECLARE val INT;
DECLARE done INT DEFAULT FALSE;

DECLARE cur CURSOR FOR SELECT id FROM my_table;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

OPEN cur;

read_loop: LOOP
  FETCH cur INTO val;
  IF done THEN
    LEAVE read_loop;
  END IF;

  SET i = i + 1;
  -- 在这里执行循环体
  SELECT val;
END LOOP;

CLOSE cur;

DECLARE cur CURSOR FOR SELECT id FROM my_table;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

OPEN cur;

read_loop: LOOP
  FETCH cur INTO val;
  IF done THEN
    LEAVE read_loop;
  END IF;

  -- 在这里执行循环体
  SELECT val;
END LOOP;

CLOSE cur;