oracle 选择最频繁出现之前，５文章数据

SELECT
*
FROM
(
SELECT
PROJECT_LISTING.MATERIAL,
COUNT (*) AS "出现次数"
FROM
PROJECT_LISTING
WHERE
PROJECT_LISTING.MATERIAL IS NOT NULL
GROUP BY
PROJECT_LISTING.MATERIAL
ORDER BY
COUNT (*) DESC
) WHERE　ROWNUM <= 5

	ORDER BY
COUNT (*) DESC　[b]是关键排序[/b]

COUNT (*) AS "出现次数"　　这不能写，只是为了看的清楚