On a single worksheet I have a small table consisting of two columns, Date &
Sales. Each row is one instance of a date with its sales. The data is in the
form of an Excel 2007 "Table". With a cell in the table selected, I click on
"Insert Pivot Table"; position it on the same worksheet as the data table; in
the Pivot Table Field List I check both Date and Sales; then select a Date
cell, Rt.Click , Click
Group, and Group by weeks (7 days); thus giving me the 1st table I want and
from which I can obtain the chart I want.

But then I try to repeat the whole process, same worksheet, same sequence,
and I get a 2nd pivot table. And now when I group the dates by Months, the
1st pivot table suddenly changes to a monthly table as well & likewise a
chart associated with it. How do I keep these two pivot tables independent
of eachother? I want to have only one master data table to which new data
can be added and not run the risk of failing to update many separate tables.