Usually the name of the group is defaulted with the first column selected in the query select statement.
Create groups when you want to treat some columns differently than others. For example, you create groups to:
· Produce subtotals (that is, totals at a more granular level).
· Create breaks or cross products in your report output.
With the exception of cross-product groups, all user-created groups are called break groups. Break groups
We used to create break groups for produce subtotals, print columns in a different direction, create breaks, and so on. A break group suppresses duplicate values in sequential records.
For example, Reports Builder can select the department number for each record; however, the duplicate department numbers are not printed.
We have to drag all the columns down in order to create break groups leaving the group column above in the query group.
Cross-product groups
We can also create cross-product groups to perform mathematical cross products, which are generally used to create matrix reports.