The main issue with group_concat is that aggregates have to keep each column in memory and that is a big problem. If The user knows the list will be small you could write a UDAF like collectset, collect which puts each value into a list and then you can lateral view that list.
Edward On Fri, May 11, 2012 at 4:02 PM, Saurabh S <saurab...@live.com> wrote: > > As far as I understand, there is no equivalent of MySQL group_concat() in > Hive. This stackoverflow question is from Sept 2010: > http://stackoverflow.com/questions/3703740/combine-multiple-rows-into-one-space-separated-string > > Does anyone know any other method to create a delimited list from from table > rows? There are a few methods listed in Anthony Molinaro's SQL Cookbook, but > all of them use over(partition by) method which is also not available in Hive. >
