3日間連続して欠席した従業員を探す

SELECT DISTINCT A.EMPLOYEENAME
FROM Attendance AS A
JOIN Attendance AS B ON B.LEAVE_DATE = A.LEAVE_DATE + 1 AND B.EMPLOYEENAME = A.EMPLOYEENAME
JOIN Attendance AS C ON C.LEAVE_DATE = B.LEAVE_DATE + 1 AND C.EMPLOYEENAME = B.EMPLOYEENAME

内部結合により、3日連続で欠席しなかったすべての従業員が削除されます。