A calculated column is a column of data that is created and added to the query results. The contents of the new column is based on an expression that you define. The expression can use data from other columns, constants and variables.
You use the Calculated Columns window to add a calculated column to the query results. You can open the Calculated Columns window by:
The expression used to calculate the value of the added column is saved with the query. The calculated column will be included in the query results each time the query is run.