Sum up value at query level

I want to sum up value at query level ]

at cube level

Material Year Period Qty

A 001.2007 100

B 001.2007 200

A 001.2007 300

C 002.2007 400

at query, I want to show it in this way. How to do that in query? I don't want to make any change in cube.

Material Year Period Qty

A 001.2007 400

B 001.2007 200

C 002.2007 400

Thanks.