I am using GROUP BY
to aggregate over an item per month. I would like the SUM
of one column and the product of another. I can't find a product operator online or in my book... but is there a series of other operators that will build the product operator?
In a pinch, I can do the product operating in R, which is where the data are heading, but I would love to minimize the amount of looping I do.
Thanks!
Update: OK, so I really wanted to create a product aggregator to send the product of a column back to R. In trying to answer a futerh downstream question I got the answer that put it all together. There's already a library of common functions not incorporated into SQLite (the Healey functions). I can easily use these functions in R using a library (RSQLite.extfuns). So I can create the product aggregator by exponentiating the sum of logs. Thanks to DWin for showing me the key piece about the RQLite.extfuns library.
You can add your own aggregate operator using create_function().