MYSQL实现连续签到功能断签一天从头开始(sql语句

CREATE TABLE `testsign` ( 
 `userid` int(5) DEFAULT NULL, 
 `username` varchar(20) DEFAULT NULL, 
 `signtime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, 
 `type` int(1) DEFAULT '0' COMMENT '为0表示签到数据，1表示签到日期字典数据' 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 

insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-21 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-22 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-23 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-24 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-25 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-26 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-27 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-28 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-29 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-30 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-05-31 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-06-01 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-06-02 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-06-03 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-06-04 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('72164','字典','2017-06-05 00:00:00','1'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('800675','吴小双签到数据','2017-05-21 00:00:00','0'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('800675','吴小双签到数据','2017-05-22 00:00:00','0'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('800675','吴小双签到数据','2017-05-23 00:00:00','0'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('800675','吴小双签到数据','2017-05-24 00:00:00','0'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('800675','吴小双签到数据','2017-05-25 00:00:00','0'); 
insert into `testsign` (`userid`, `username`, `signtime`, `type`) values('800675','吴小双签到数据','2017-05-26 00:00:00','0'); 

SELECT  FROM testsign WHERE TYPE=0 AND 
 DATE_FORMAT(signtime,'%Y%m%d')>( 
 SELECT IFNULL(MAX(DATE_FORMAT(signtime,'%Y%m%d')),"20170520") FROM testsign WHERE TYPE=1 
 AND DATE_FORMAT(signtime,'%Y%m%d')<=DATE_ADD(NOW(), INTERVAL -1 DAY) 
 AND DATE_FORMAT(signtime,'%Y%m%d') NOT IN ( 
    SELECT DATE_FORMAT(signtime,'%Y%m%d') FROM testsign WHERE TYPE=0 AND userid=800675 
    ) 
 ) 
 AND DATE_FORMAT(signtime,'%Y%m%d')<='20170605' 
 AND userid=800675