Using Group By to Select Max Date


I am trying to select the maximum date in one field for a unique identifier in another field
Current Spreadsheet
Unique ID Date
1 6/1/2010
1 1/2/2013
1 4/1/2000
1 7/9/2017
2 9/13/2015
2 8/8/1972
2 8/29/1999
2 3/27/2018
3 1/1/2018
3 12/15/2017
3 4/1/2013
3 2/18/2000
4 5/1/2000
4 1/6/1999
4 2/27/2018
4 4/27/2014

Desired Result
Unique ID Date
1 7/9/2017
2 3/27/2018
3 1/1/2018
4 2/27/2018

I looked through some other threads and saw suggestions to use the Group By node and then a row filter. I could not figure out how to configure the Group By node -

Looking for suggestions

Thank you!

In the ‘Groups’ tab, Add your ‘Unique ID’ column. In the ‘Manual Aggregation’ tab, add the ‘Date’ column, and then in the dropdown which appears next to it, select ‘Maximum’


This is close, but @MapperKnime will need to convert the dates to Date&Time format first, perhaps using the String to Date&Time node. Otherwise the maximum aggregation in the GroupBy node returns an incorrect answer.

I threw together this quick workflow DateConversionGroupByExample.knwf (8.7 KB):


which returns the following as output:

Note that I changed the format of the input date slightly to play nicely with the String to Date&Time node.


@ScottF - I was assuming they were already date cells hence not mentioning that - thanks for the extra clarification!


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