[snip] The mathematical way to add two "partial" harmonic means to generate new harmonic mean is:
Let X1 , X2 be two harmonic means on different rollup rows, generated using n1 and n2 # of facts respectively. The combined harmonic mean would be: (n1 + n2)/( n1/x1 + n2/x2) If you have experience with computing harmonic mean in SQL, please share. [/snip] Unless I am misunderstanding your question the simplest method would be; SELECT ((n1 + n2)/(n1/x1 + n2/x2)) AS "Harmonic Mean" ...without knowing the structure of the data. If X1 and X2 live on 2 different rows you could write a stored procedure to retrieve the relevant data and produce an output. -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
