SELECT department_id, last_name, salary, PERCENT_RANK() OVER (PARTITION BY department_id ORDER BY salary) AS pr FROM employees WHERE department_id < 50 ORDER BY department_id,salary;
PERCENTILE_CONT 功能描述:返回一个与输入的分布百分比值相对应的数据值,分布百分比的计算方法见函数PERCENT_RANK,如果没有正好对应的数据值,就通过下面算法来得到值: RN = 1+ (P*(N-1)) 其中P是输入的分布百分比值,N是组内的行数 CRN = CEIL(RN) FRN = FLOOR(RN) if (CRN = FRN = RN) then (value of expression from row at RN) else (CRN - RN) * (value of expression for row at FRN) + (RN - FRN) * (value of expression for row at CRN) 注意:本函数与PERCENTILE_DISC的区别在找不到对应的分布值时返回的替代值的计算方法不同