This currently is not possible, considering the existence of flatten is should definitely be added. There is a larger issue that we do not support all of the patterns that users will expect with lists. Drill is also unable to apply a scalar function over all of the elements of a list, or apply an arbitrary aggregate function over a list. A few UDFs like repeated_count have been defined but it would be best to have a more general solution. We also are unable to do anything with a nested value and then place it back into the same nested position in the schema. Our aliases only support storing back into the root of the schema currently.
-Jason Altekruse On Fri, Feb 27, 2015 at 8:25 AM, Ted Dunning <[email protected]> wrote: > I was just looking through the documentation and I don't see a way to group > data and then create a list. Flatten turns a list into individual > records. I would like to turn some fields from a grouped set of records > into a list of objects or a list of values. >
