sql考勤

⑴ 如何在sql資料庫里再增加一個打卡時間，以圖片數字為列

用sql語句
alter table 考勤表 ADD clock time time stamp就可以了
然後更新你的欄位值

⑵ sql語句實現考勤報表，sql語句怎樣實現員工同一天只有兩次考勤

兩次考勤：select 員工ID,TRUNC(TIME,'d') FROM 考勤表 group by 員工ID,TRUNC(TIME,'d')

having count(*)=2;
漏打：select 員工ID,TRUNC(TIME,'d') FROM 考勤表 group by 員工ID,TRUNC(TIME,'d')
having count(*)<2;