cume_dist vs percent_rank or difference between
oracle, plsql, sql
Solution
Are you asking what these functions do?
http://docs.oracle.com/cd/B19306_01/server.102/b14200/functions035.htm
CUME_DIST calculates the cumulative distribution of a value in a group of values.
In your example this means that ~29% has less or equal height than buddy. ~57% has less or equal height than lauren. Etc.
http://docs.oracle.com/cd/B19306_01/server.102/b14200/functions109.htm
PERCENT_RANK is similar to the CUME_DIST (cumulative distribution) function. The range of values returned by PERCENT_RANK is 0 to 1, inclusive. The first row in any set has a PERCENT_RANK of 0. The return value is NUMBER.
Problem
In the following query i return different result but can't figure out the what are this two functions. ``` select firstname,gender,weight,height, cume_dist() over (order by height) cd, percent_rank() over (order by height) pr from childstat order by height ``` ``` FIRSTNAME GENDER WEIGHT HEIGHT CD PR -------------------------------------------------- ------ ---------- ---------- ---------- ---------- buddy m 150 15 0.2857142857 0 Albert m 923 15 0.2857142857 0 rosemary f 123 35 0.4285714286 0.3333333333 lauren f 876 54 0.5714285714 0.5 furkar m 198 76 0.7142857143 0.6666666667 tommy m 167 78 0.8571428571 0.8333333333 simon m 256 87 1 1 ```