Filter for most recent record within each group

Discussion created by shepa006 on Dec 5, 2012
We're connecting to a WFS via the Data Interop extension and have some OGC filtering applied. The next step that we would like to take is filtering by the maximum date value within each group ID. There multiple records all with the same group ID and we only need to show the most recent record (but include all attributes for it). One group ID could have 10+ records so limiting that to only the most recent will really reduce the processing.