Adding values within date ranges

Hello,

New to this site - so sorry if this was covered already.

I have a spreadsheet that I'm working on - and I'm simply stumped on how to do something.

I have several part numbers that we've been selling. While I can easily determine the total of each part sold since the beginning, I can't figure out use excel to look at the part numbers within a certain time period & add up the total qty sold of each item during the last 12 months & 6 months. (Need to know to help in forecasting)

My spread sheet is laid out with the following

B Column - Job Number.
C Column - Client Part Number.
D Column - My part number.
E column - Description of part.
F Column - Qty Sold.
H Column - Ship date.

I'm trying to determine:
1. How many of each of the Client P/N#'s shipped in the last 12 months, and
the last 6 months.

2. How many of each part (with my Part numbers) shipped during the same
time period.

Any help would be highly appreciated!

Thanks,
Kyle