Calculate accumulated value and grouping

Hi,

If I have 2 datasets

Dataset 1 is a grouped dataset based on Region, As of date, Type, Customer, as follow

Region        As of date       Type       Customer      Accum. Sales Amount

A                  7-Jan-17            New        001                 1000

A                  7-Jan-17            New        002                 1500

A                  7-Jan-17            New        003                 700

B                  7-Jan-17            Old          004                 300

B                  7-Jan-17            Old          005                 400

etc

Dataset 2 consists of delivery data in a raw data (transactional data) format

Question:

How to calculate the accummulated amount of delivery with the same period with As of date value in the 1st dataset, and also to group the data same as the 1st dataset? Since this two data needs to be combined and calculated.

Thank you