Back in 2014 I wrote a blog post on how to calculate a median value using the NTILE window function. It’s far from the best performing solution there is, but it worked on SQL Server 2008, before the introduction of OFFSET-FETCH i SQL Server. In this post, I’m going to look at creating a generalized function that calculates the median (or any percentile) of a series of values.
A while back, I was shown an absolutely gorgeous median calculation, using the new OFFSET/FETCH functionality introduced in SQL Server 2012. But this got me thinking. How can you calculate the median in an older SQL Server? Here’s an idea of how to do it using the NTILE() function.