I have the following repair records with headers in row 1, and data beginning
in row 2.
All data is contiguous down the columns with no spaces. I inserted the
lines between the different serial numbers for reading clarity.

[col A] [col B] [col C] [col D]
Start Date Ticket Number Serial Number Repeat Repair Count
12/29/2007 123 ABC111 0

08/28/2008 234 BCD222 0
08/28/2008 234 BCD222 0

12/29/2007 345 CDE333 0
08/26/2008 456 CDE333 1
12/17/2008 567 CDE333 2

11/12/2008 678 DEF444 0

06/14/2008 789 EFG555 0
12/16/2008 890 EFG555 1


I need to produce a report of repeat repair activity after the initial
repair. After sorting the data by serial number, by ticket number, by start
date, I have to look at the serial number it matches, then check the tcket
number to see if it doesn't match.

Using the data above, my report would read as follows:

Three serial numbers ABC111, BCD222, DEF444 had no repeat repair activity
One serial number EFG555, had 1 repeat repair
One serial number CDE333 had 2 repeat repairs

I'm stumped....can anyone help with a way to fill in the counts in col D?

Thank you.....