Data Access Studio lets you easily sum up multiple columns into a new totals column.

To sum columns, multi-select the columns you need by clicking the column headers while holding down the CTRL or SHIFT keys.

Right-click any column header in your selection, and select Quick Calculation > Math > Sum.

Note: If your layout is grouped, the sum column will show totals for each summary line and grand totals as well.

If you want to add a grand total at the bottom of the sum: