Okay I think I'm making this harder than it should be. I need help!

I am making a summary sheet with several other sheets that hold data.
columns are the same in all the data sheets just the info is different by
part #, store #, store ranking, and qty. I am trying to make a summary page
that when I put this part # in this cell b1 on the summary sheet it will look
at all the data sheets find the part # and if it has this type ie. "A"
ranking in A12 on the summary sheet as well... then sumif the total in this
column "i4:i291" on each data sheet it finds. I need to have at least 7 Data
sheets. Because I have about 200 part # and 1000 stores.

This might not be the right formula to use. So, any help would be GREAT!

=IF(Data1!$A$4:$A$291=summary!$B$1,SUMIF(Data1!$G$ 4:$G$291,$A12,Data1!$I$4:$I$291)IF(Data2!$A$4:$A$2 91=summary!$B$1,SUMIF(Data2!$G$4:$G$291,$A12,Data2 !$I$4:$I$291))

thanks so much, B.