Sort by multiple criteria

Google Refine sort function allow a combination of several columns to sort by field A and field B. 

In my case, I used this method as a work extract the most recent title posted from a records in a list of radio show (using a timestamp field). As I am not aware for a way to select a specific row within a record, I used the sort function to present the record I wanted to extract at the top my the record group.

So our initial data set look like this and we want the initial postDate first for every album (in the screenshot below I already sort by album name).

Select and sort the column you want as initial sort, in our case this is the album field:

Then select the second column you want to sort. This second sort will take into account the initial sort by album. You can create a non dependant sort by clicking the option sort by this column alone

Final result, we have the the initial post time displayed first.

After that you can export only the first row of every records by removing all the other rows (the process is quite similar to the one to remove duplicate).