Hello Amrit,
one option would be to join the original table with the grouped table to add the max information to the existing table. However if you want to apply more complex sql queries you can temporary write your data table into a SQLite db, which is a file based db that does not need any installation. Once you have your data in SQLite you can query it with the database nodes. See attached workflow for an example.
Hint: The SQLite connector is part of the KNIME Connectors for Common Databases feature.
Bye,
Tobias