Ah - Thanks so much. I didn't know you could reference a column that has an aggregate function call again in the same select statement. This is much cleaner that the approach that I took. I'll give it a shot.
Thanks again. On Wed, May 27, 2009 at 4:24 AM, Amr Awadallah <[email protected]> wrote: > I agree that a builtin for std dev is a good idea. > > that said, you can achieve this easy in one pass, just use: > > select sum( pow(col,2) ) as totsqr, sum( col ) as tot, count(1) as n, pow( > (n*totsqr - pow(tot,2) )/(n*(n-1)), 0.5) as stddev > from .... > > > Matt Pestritto wrote: > >> Hi. >> >> Are there plans to write a standard deviation aggregate function ? I had >> to build my own which translated into multiple hive queries. While it >> works, a build-in function would have been much easier. >> >> Thanks >> -Matt >> >
