My MS SQL skills are under great test at the moment. I was wondering if
I could get some help on this problem.

So I have a Query which is pulling fields from different tables.
Below are the date elements of my query

FIELD NAMES

* Sum Of total Planned Sales (A sum of revenue from Table 1)

* Total Hrs (Total Air hours + Total Car hours + Total idle time) This
is also a summation field made up of three separate fields - Taken
from Table 2

* Functional ID - A ID assigned to a location - Taken from Table 1

I have data sets which look like the following

Functional ID            Total Hours       Sum of total Planned Sales
3344                66                $4500
3344                66                $4500
3346                66                $4500
3347                66                $4500
3347                66                $500
3349                66                $4500

This looks fine except when duplicate Funtcional IDs comes with a
diffent value for 'total planned sales. '

I want a query that will add the total hours per functional ID BUT if
there is a duplicate with a different 'Sum of Total planned Sales'
then I want the 'Total Hours' for the lower value of 'total
planned sales' equal to 0. Such is the case with Functional ID 3347.