stored proc looping through returned result from select

I want to use the following procedure to firstly pull in all business units associated with a business area then count the number of projects associate with all of the business units returned.

I am fairly new to stored procs and know that what I have written is not correct but I am not sure how or if I can do this.

Any help would be greatly appreciated.

CREATE PROCEDURE sp_projSplitByBusUnit AS
@busAreaId int -- Used to Pull In Bus Area Value
@busUnits -- Used to store return from first select statement
busUnitCount varchar return
BEGIN

SELECT t_bus_areas.f_bus_unit_id, t_bus_areas.f_name
FROM t_bus_units
WHERE f_bus_area_id = @busAreaId

-- Loop through returned records to pull in buiness areas

for i = 0 to uBound(@busUnits, 2)
busUnitCount & i = count *
FROM t_proj
WHERE f_bus_unit_id = @busUnits(i)
next

END

GO

It sounds to me like what you really want is group by clause.