Here is how I was able to get the results I required. I'm sure there are
other ways (and probably simpler than the methods I used).
I utilized some columns that were out of sight of easy viewing. Pete I
utilized your FLOOR formula. My actual spreadsheet contained 2073 rows.
Here are the formulas I used.
Column AH2 contains: =FLOOR(MIN(A2:$A$2073),1/24)
Column AH3 contains: =FLOOR(MIN(A3:$A$2073),1/24)
I then copied AH3 down to AH2073. This gave me a list of all my times in
the format of MM/DD/YY HH:00:00. Column AH contained duplicates. To remove
the duplicates, I entered the formula below into Column D:
=IF(ISERROR(SMALL(AJ:AJ,ROW())),"",INDEX(AH:AH,MAT CH(SMALL(AJ:AJ,(ROW()-1)),AJ:AJ,0)))
This is an array formula and has to be entered with SHIFT+CNTL+ENTER. I
copied it down to D2073.
I then entered the following in Column AJ2:
=IF(AH2="","",IF(COUNTIF($AH$2:AH2,AH2)1,"",(ROW( )-1)))
This too is an array formula and has to be entered with SHIFT+CNTL+ENTER. I
copied it down to AJ2073.

The combination of the two formulas eliminated my duplicate dates in Column
D. In Column C2 I entered:
=SUM((AH2:AH2073=C2)*(B2:B2073))
This is another array formula and required to be entered with
SHIFT+CNTL+ENTER. I copied it down to C2073.

One more thing, the columns containing dates had to be preformatted to the
date format I wanted prior to putting the formulas in them.

Thanks again Pete_UK and David Biddulph.

Mike

"MikeK" wrote:

I have two columns. Column A is a date time column. Column B is an amount
column. I want to calculate the amounts by the hour and place the hourly
totals in Column C and the date time of that hour in Column D. Below is an
example of the data and how I would like Column C and Column D to look.

Column A Column B Column C Column D
DATE AMOUNT TOTALS/HR DATE
01/01/2009 01:10:10 50 75
01/01/2009 01:00:00
01/01/2009 01:20:05 25 10
01/01/2009 02:00:00
01/01/2009 02:01:00 10 45
01/01/2009 03:00:00
01/01/2009 03:05:25 15 20
01/02/2009 05:00:00
01/01/2009 03:07:59 30
01/02/2009 05:05:01 20

I posted this earlier but couldn't find my post. I guess I did it
incorrectly. Any help would be appreciated. If the alignment is skewed
below is the information per column.
Column A
DATE
01/01/2009 01:10:10
01/01/2009 01:20:05
01/01/2009 02:01:00
01/01/2009 03:05:25
01/01/2009 03:07:59
01/02/2009 05:05:01

Column B
AMOUNT
50
25
10
15
30
20

Column C
TOTALS/HR
75
10
45
20

Column D
DATE
01/01/2009 01:00:00
01/01/2009 02:00:00
01/01/2009 03:00:00
01/02/2009 05:00:00