select classId , avgPoints , lag(avgPoints, 1) over (order by classId) prevAvg , lead(avgPoints, 1) over (order by classId) nextAvg from ( select '2-1' classId , 98.3 avgPoints from dual union all select '2-2' classId , 72.5 avgPoints from dual union all select '2-3' classId , 58.9 avgPoints from dual union all select '2-4' classId , 88.2 avgPoints from dual ) //-------------조회결과----------------..