• the addition of an operation into a Select query.
• the deletion of an operation from a Select query.

Adding an operation into the current Select query

1. On the "Query" tab, in the "Edit" group, click "Description". The query description window appears.
2. In the middle section, select the item on which an operation must be performed.
3. To calculate:
   • the sum of the values in the item, click on "Sum...".
   • the average of the values in the item, click on "Average, Max, Min" and select "Average".
   • the maximum value of the values in the item, click on "Average, Max, Min" and select "Maximum".
   • the minimum value of the values in the item, click on "Average, Max, Min" and select "Minimum".
4. An item corresponding to the requested calculation is automatically added to the query items.
5. Validate. The operation is automatically added into the query.

Deleting an operation from the current Select query

1. On the "Query" tab, in the "Edit" group, click "Description". The query description window appears.
2. In the middle section, select the calculation item to delete.
3. Press the Del key.