Question

Excel has the KURT function that returns the kurtosis of a data set. Does SQL Server have an equivalent aggregate function?

Answer 1

TSQL has all of the functions required to calculate kurtosis, but I think you’d have to put it all together yourself in a custom function.

Here’s one implementation I found (ref: SolidQ)

SELECT 
   Kurt = SUM(SQUARE(SQUARE(((Age*1.0-m.mean)/m.[StDev])))) * MIN(m.corrfact2) - MIN(m.subfact)
FROM 
      vTargetMail v 
   CROSS JOIN
      (
       SELECT 
          mean = AVG(Age*1.0), [StDev] = STDEV(Age),
          corrfact2 = COUNT(*)*1.0 * (COUNT(*)+1) / (COUNT(*)-1) / (COUNT(*)-2) / (COUNT(*)-3),
          subfact = 3.0 * SQUARE((COUNT(*)-1)) / (COUNT(*)-2) / (COUNT(*)-3)
       FROM vTargetMail v
      ) AS m;