Hi, I have a dataset with two three columns, group_id, position, and name. I need for each group to generate a concatenated string of all names ordered by their position. I can do this by sorting all data based on position, (or group_id and position), then grouping them by group_id, and finally concatenating names in each group. I have two questions here, 1- Does this really work? In other words, does the GROUP BY operator retain order? 2- What is the most efficient way to do it? Is it better, if possible, to group first and then sort? Let's say I order by the pair (group_id, position) first, can this be hinted to Pig to make the group by faster. Thanks for your help
Best regards, Ahmed Eldawy
