yogi_Compute Sum Of Specified Entities Over Specific Period Of Time

Yogi Anand, D.Eng, P.E.                                         Google Spreadsheet                            www.energyefficientbuild.com
herkalaska said:
SUM from a FILTER in a range from NOW and the previous 30 days
I am building a Pilot logbook in a Google spreadsheet. I would like to SUM flight hours from each aircraft in a current date range.
Sheet 1
column A column B column C
date aircraft hours
9/1/2011 C-172 3.5
9/2/2011 C-206 4.5
10/1/2011 C-172 1.2
10/2/2011 C-206 5.5
I want to get all the hours from the C-172 for the past 30 days in a cell on a seperate sheet
IE; If todays date was 10/15/2011 the cell would = 1.2
I would also like the same info for the past 6 months. Then the above example would = 4.7
The product would look like this;
Sheet 2
column A column B column C
aircraft past 30 days past 6 months
C-172        1.2          4.7
C-206        5.5         10.0
I have tried a few formulus from other help posts but I havnt found any that combine all three cells
------------------------------------------------