Originally posted by Countrystyle
The only other way I can think of is to write a formula using the 'dayofweek' formula to determine the numeric value of the day of the week. You can then assign names to the values and then group by week periods. You may have to add a month and year formula if you want then separated even further.
try this..
{CUSTOMER_ORDER.DATE_ENTERED} = your field group by weekly.
dateadd("ww",datepart("ww",{CUSTOMER_ORDER.DATE_ENTERED}, crMonday)-1,
date(year({CUSTOMER_ORDER.DATE_ENTERED}),1,1)-dayofweek(date(year({CUSTOMER_ORDER.DATE_ENTERED}),1,1),crMonday)+1)