Thanks for your response. For instance, I use the query wizard to create a new crosstab query. The table I am using for the crosstab query contains many records including quantities and dates for each record. The wizard asks which interval I want to group the dates by and gives me these choices: year, quarter, month, date, date/time. Usually I select months, but I would really like the totals to be by weeks. If the wizard does not offer this option, I'd like to know the correct expression so I can total by weeks using the expression.