mybatisplus日期条件查询

求教一个问题，mybatisplus在拼接sql where语句时，一个时间范围判断，传入的时间参数是date类型和string类型有什么区别，数据库用的mysql，string字符串也是标准的yyyy-MM-dd格式

个人感觉区别不大，数据库与mybatis都会去自行识别的 

　String dzDate = "20200804";
//         dzDate = "\uFEFF20200804";
        SimpleDateFormat sdf1 = new SimpleDateFormat("yyyyMMdd");//注意月份是MM
        SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd");//注意月份是MM
        Date dzDateObj = sdf1.parse(dzDate);
        String startDayTime = sdf2.format(dzDateObj)+" 00:00:00"; //2020-08-04 00:00:00
        //加一天
        Calendar cal = Calendar.getInstance();
        cal.setTime(dzDateObj);
        cal.add(Calendar.DAY_OF_YEAR,1);
        Date addDate = cal.getTime();
        String endDayTime = sdf2.format(addDate)+" 00:00:00";//2020-08-05 00:00:00
        //查询指定字段
        paySerialQueryWrapper.select("PAY_SERIAL_ID","PAY_CHANNEL_SERIAL","AMOUNT");
        //查询条件为时间范围
        paySerialQueryWrapper.apply("UNIX_TIMESTAMP(PAY_DATE) >= UNIX_TIMESTAMP(‘"+startDayTime+"‘)");
        paySerialQueryWrapper.apply("UNIX_TIMESTAMP(PAY_DATE) < UNIX_TIMESTAMP(‘"+endDayTime+"‘)");
        //查询当天所有支付记录
        List<PaySerial> pcPaySerials = paySerialService.list(paySerialQueryWrapper);