SQL Server 2012 introduces new analytical function PERCENTILE_CONT().
The book online gives following definition of this function: Calculates a percentile based on a continuous distribution of the column value in Microsoft SQL Server 2012 Release Candidate 0 (RC 0). The result is interpolated and might not be equal to any of the specific values in the column.
If you are clear with understanding of the function – no need to read further. If you got lost here is the same in simple words – it is lot like finding median with percentile value.
Now let’s have fun following query:
SELECT SalesOrderID, OrderQty, ProductID,
PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY ProductID)
OVER (PARTITION BY SalesOrderID) AS MedianCont
WHERE SalesOrderID IN (43670, 43669, 43667, 43663)
ORDER BY SalesOrderID DESC
The above query will give us the following result:
You can see that I have used PERCENTILE_COUNT(0.5) in query, which is similar to finding median. Let me explain above diagram with little more explanation. The defination of median is as following:
In case of Even Number of elements = In ordered list add the two digits from the middle and devide by 2
In case of Odd Numbers of elements = In ordered list select the digits from the middle
I hope this example gives clear idea how PERCENTILE_CONT() works.
Reference: Pinal Dave (http://blog.SQLAuthority.com)