Grouping on multiple columns
Just as you do when you sort on multiple columns, consider order of precedence before creating groups. To group customer data by state, then by city, create the groups in that order. For example, the report design in Figure 4-7 groups sales data first by sales office, then by product line. You can identify the order of the data groups by the order of the columns in the table. The first group appears as the first column in the table, the second group appears next to it, and so on.

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