Tutorial by Examples

The MEDIAN function since Oracle 10g is an easy to use aggregation function: SELECT MEDIAN(SAL) FROM EMP It returns the median of the values Works on DATETIME values too. The result of MEDIAN is computed by first ordering the rows. Using N as the number of rows in the group, Oracle calcula...

Variance measures how far a set numbers is spread out from it's mean. From practical perspective it is squared distance from its mean (center) - the bigger the number the farther the point is. The following example would return variance of salary values SELECT name, salary, VARIANCE(salary) "...

STDDEV returns the sample standard deviation of expr, a set of numbers. You can use it as both an aggregate and analytic function. It differs from STDDEV_SAMP in that STDDEV returns zero when it has only 1 row of input data, whereas STDDEV_SAMP returns null. Oracle Database calculates the standard ...