今天看书讲T-SQL，看到了UNBOUNDED PRECEDING，就想比对下ROW_NUMBER()的运行速度。
sql及相关的结果如下，数据库中的数据有5W+。
ROW_NUMBER()：
SET STATISTICS TIME ON
SELECT
ROW_NUMBER() OVER(ORDER BY Id DESC) rn,Id
FROM
dbo.T_MyCourse
运行结果
UNBOUNDED PRECEDING
SET STATISTICS TIME ON
SELECT
SUM(1) OVER(ORDER BY Id DESC ROWS BETWEEN UNBOU
