MySql 根据子类id提取所有父类修改

DROP FUNCTION getTopId;
DELIMITER $$
CREATE FUNCTION getTopId(inputId INT) RETURNS INT
BEGIN
  DECLARE result_id INT;
  DECLARE input_id INT;
  SET input_id = inputId ;
  REPEAT
    SET result_id = @d;
    SELECT COUNT(*),b INTO @c, @d FROM test WHERE a = input_id;
    SET input_id = @d;
  UNTIL (@c = 0)
  END REPEAT ;
  RETURN result_id;
END $$SELECT a,getTopId(a) FROM test