Format column E as hh:mm:ss then try entering:

=SUMIF(A:A,LEFT(D2,3)&"*",B:B)

On Feb 2, 9:37 am, kippers wrote:
Hi,

I have a set of call stats that have been reported in half hourly format.
One of the stats is the 'Longest Call Duration'. I am looking to convert this
data into hourly format and so I need to compare the data in two cells (i.e.
the longest call for each half hour), select the largest and place this
figure in a separate cell (the hourly cell):

A B D E
1 Time period Longest Call Time period Longest Call
2 00:00-00:30 00:01:42 00:00-01:00 ?
3 00:31-01:00 00:00:42 01:01-02:00 ?
4 01:01-01:30 00:01:41 02:01-03:00 ?
5 01:31-02:00 00:01:46
6 02:01-02:30 00:02:11
7 02:31-03:00 00:00:35

Any help gratefully appreciated!

Cheers,