Using Sumifs

[tomferrin]

I am trying to figure out the total amount of donations by each individual
donor during last year. My spreadsheet records each gift on a separate line.
Some donors have given once, others as much as 12 times. How can I create a
formula that gives the sum of donation by each individual? Is sumif the
correct formula to use?
My spreadsheet has over 7000 rows!

I've tried this formula =SUMIFS(O3:O7,D37,"=*") (I've only tried a small
range to test my formula)
O3 to O7 is the column and range for the donation amount
D3 to D7 is the last name column
and "=*" was my attempt to condition the sum on similar last names.

Because I have several donors with the same last name, would it be better to
use their unique donor ID# to be a condition?

 

[Gary''s Student]

Consider using a Pivot Table. See:

http://peltiertech.com/Excel/Pivots/pivottables.htm

 

[Bob Phillips]

You will need some sort of helper column to determine whether last names are
similar, based upon some user defined (you) rule.

 

[klswvu]

It would be better to use donor ID since this is your unique ID or
concatenate the name with the donor ID. After that, you will need to derive
the unique IDs and construct the sum formulas or use a pivot table, which is
the best option.