SQL Server 2008 介绍大家一个有趣的函数NTILE
通常有这样的需求，需要将数据按照某一字段分组，比如按成绩排列，将前25%为优秀，25%到50%有良好，50%到75%为差，75%到100%为不及格的情况。像这样需要将一个有序整体按照一定的比例划分数据的情况下，直接使用NTILE函数可以起到事半功倍的效果。NTILE(num)Num为要等分的数量
如
--NTILE分类函数 IF EXISTS (SELECT 1 FROM SYSOBJECTS WHERE name = 'tba') BEGIN DROP TABLE tba END GO CREATE TABLE tba ( ID INT IDENTITY(1,1) NOT NULL, Total INT ) GO INSERT INTO tba SELECT '100' UNION SELECT '101' UNION SELECT '102' UNION SELECT '103' UNION SELECT '104' UNION SELECT '105' UNION SELECT '106' UNION SELECT '107' UNION SELECT '108' UNION SELECT '109' UNION SELECT '110' GO SELECT ID, Total, CASE NTILE(4) OVER (ORDER BY Total DESC) WHEN 1 THEN '25%' WHEN 2 THEN '25%-50%' WHEN 3 THEN '50%-75%' WHEN 4 THEN '75%-100%' END AS Level FROM tba /* ID Total Level 11 110 25% 10 109 25% 9 108 25% 8 107 25%-50% 7 106 25%-50% 6 105 25%-50% 5 104 50%-75% 4 103 50%-75% 3 102 50%-75% 2 101 75%-100% 1 100 75%-100% */
