PowerPivot: Grouping By Dates (Months, Quarters, Years, etc.) in PivotTables
When you create a PivotTable that is based on Excel data, you can group the data in the PivotTable. For example, the source data for a PivotTable might contain a column that stores the sales date, but you can also see the data grouped by quarters or months, rather than days.
Note: You can use grouping for other types of data, but I will focus on dates here.