One way to do this I found:
Tables>Summary and Grouping by Date and Hour (in this order).
To have a column with the complete date, and not splitted by two: include in the Statistics min(Date), being median or max are also possible.
Here is a simpler example aggregating the Lead Production Data table by year.
![jmp_aggregation.png jmp_aggregation.png](https://community.jmp.com/t5/image/serverpage/image-id/17431i519A4CD7CC16E277/image-size/large?v=v2&px=999)