在很多时候，我们需要统计数据的排名情况，最常见的是成绩、投票数等等的。但是，在SQL SERVER 2005 之前，SQL SERVER 2000 并没有提供这个直接的函数供我们使用，同样 ACCESS 也是如此。
access:
select name, score, (select iif(isnull(sum(1)), 1, sum(1) + 1) from score_rank where score > a.score) as rank from score_rank a order by score desc
sql 2000:
select name, score, (select ISNULL(sum(1),0) + 1 from score_rank where score > a.score) as rank from score_rank a order by score desc
sql 2005:
SELECT name, score, RANK() OVER (ORDER BY score DESC) AS [rank], DENSE_RANK() OVER (ORDER BY score DESC) AS [rank1], NTILE(4) OVER(ORDER BY score DESC) AS [rank2] FROM score_rank ORDER BY score DESC;
select sum(1)的使用
select count(*)返回所有满足条件的记录数，此时同select sum(1)
但是sum()可以传任意数字，负数、浮点数都可以，返回的值是传入值n*满足条件记录数m 简单理解就是行数*1