mysql distinct 之后使用limit 翻页失效

问题遇到的现象和发生背景

建表语句

CREATE TABLE `tt` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `order_no` varchar(30) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `order_no` (`order_no`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;

批量造数据

DELIMITER $$
CREATE PROCEDURE process_test3()
BEGIN
DECLARE yourid INT;
SET yourid = 1;
WHILE yourid < 2000000 DO
INSERT INTO tt (order_no)

VALUES(yourid);
SET yourid=yourid+1;
END WHILE;
END;

CALL process_test3();
用代码块功能插入代码，请勿粘贴截图

select distinct order_no from tt limit 50000,500
与
select distinct order_no from tt limit 50500,500
两者查询出来的数据一模一样，当然有其他方法可以替代，但是我不懂这种情况出现的原理是什么

去掉distinct结果就不一样嘛