oracle创建管理员账号密码是什么原因oracle选取出现次数最多的前５条数据

SELECT*FROM(SELECTPROJECT_LISTING.MATERIAL,COUNT (*) AS "出现次数"FROMPROJECT_LISTINGWHEREPROJECT_LISTING.MATERIAL IS NOT NULLGROUP BYPROJECT_LISTING.MATERIALORDER BYCOUNT (*) DESC) WHERE　ROWNUM <= 5

ORDER BYCOUNT (*) DESC　是关键排序

COUNT (*) AS &oracle账号quot;出现次数"　　这个可以不写，只是为了看的明白