Edit Group By

Default Type: Column
You can change the Type to: Expression

• If Type is Column, then select one or more columns in the Available Attributes list. You can search the list by name or by data type. Move the selected columns to the Selected Attributes list using the arrows.

• If the Type is Expression, then type an appropriate expression in the Expression box.
  Click Validate to validate the expression.

After you are done, click OK.