Supposed you use the core Table widget, there's a "formatValue" property of columns that allows users to change a column value based on the current data row like this:

    Table::create(array(
        ...
        "columns"=>array(
            "amount"=>array(
                'formatValue'=>function($value, $row, $cKey)
                {
                    //return a custom value based on the current $row and column name $cKey
                    return $customValue;
                }
            ),
        ),
        ...
    )); 

By core Table I meant \koolreport\widgets\koolphp\Table:

https://www.koolreport.com/docs/koolphp/table/#table-settings-format-column-value

\koolreport\datagrid\DataTables also has column formatValue option:

https://www.koolreport.com/docs/datagrid/datatables/#format-column-value