SELECT a.uid, COUNT(IF(submit_time IS NULL,uid,NULL)) AS incomplete_cnt, COUNT(IF(submit_time IS NOT NULL,uid,NULL)) AS complete_cnt, GROUP_CONCAT(DISTINCT CONCAT(DATE(a.start_time),':',b.tag) ORDER BY DATE(a.start_time),b.tag SEPARATOR ';') AS detail # 这里直接连start_time就行,因为要求是作答过的 F...