"JR Bullington" <[EMAIL PROTECTED]> wrote: > This is for those who love a challenge. > > I am trying to come up with a query that would calculate the Standard > Deviation and Variance for 15 fields. Although in theory this is easily done > in Access, MySQL does not have the same mathematical calculations that > Access/SQL does. > > Here is the query as it stands in Access: > > Select avg(Item01) as Item01a, stdev(Item01) as Item01d, avg(Item02) as > Item02a, stdev(Item02) as Item02d, avg(Item03) as Item03a, stdev(Item03) as > Item03d, avg(Item04) as Item04a, stdev(Item04) as Item04d, avg(Item05) as > Item05a, stdev(Item05) as Item05d, avg(Item06) as Item06a, stdev(Item06) as > Item06d, avg(Item07) as Item07a, stdev(Item07) as Item07d, avg(Item08) as > Item08a, stdev(Item08) as Item08d, avg(Item09) as Item09a, stdev(Item09) as > Item09d, avg(Item10) as Item10a, stdev(Item10) as Item10d, avg(Item11) as > Item11a, stdev(Item11) as Item11d, avg(Item12) as Item12a, stdev(Item12) as > Item12d, avg(Item13) as Item13a, stdev(Item13) as Item13d, avg(Item14) as > Item14a, stdev(Item14) as Item14d, avg(Item15) as Item15a, stdev(Item15) as > Item15d, avg(overallscore) as overa, stdev(overallscore) as overd from > tblFacultyEvalSurgery > > This is for an online grading system that, except for 5 pages, has been > converted over to MySQL and Linux / Apache. 2 of which have this problem. > > Avg() is easy, but it's the StDev that I can't get. St Dev is made from > Variance (or the mean), which again is not a function of MySQL. > > To view the Variance and StDev formulae, > http://davidmlane.com/hyperstat/A16252.html. > If you have any ideas, I will > be working on this for the next few days.
There are STD()/STDDEV() functions in the MySQL: http://www.mysql.com/doc/en/GROUP-BY-Functions.html -- For technical support contracts, goto https://order.mysql.com/?ref=ensita This email is sponsored by Ensita.net http://www.ensita.net/ __ ___ ___ ____ __ / |/ /_ __/ __/ __ \/ / Victoria Reznichenko / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.net <___/ www.mysql.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]