SSRS - How to total a row - reporting-services

Question

Report Month Booked Month Hours Available Hours Reported Hours
2015-12-01 00:00:00 2015-10-01 00:00:00 3.5 97 172
2015-12-01 00:00:00 2015-10-01 00:00:00 0.75 97 172
2015-12-01 00:00:00 2015-10-01 00:00:00 6.85 97 172
2015-12-01 00:00:00 2015-10-01 00:00:00 3 97 172
2015-11-01 00:00:00 2015-10-01 00:00:00 3.5 97 185
2015-11-01 00:00:00 2015-10-01 00:00:00 0.75 97 185
2015-11-01 00:00:00 2015-10-01 00:00:00 6.85 97 185
2015-11-01 00:00:00 2015-10-01 00:00:00 3 97 185
In my SSRS report i want to total the Reported Hours Column. This person booked 172 hours in December and 185 hours in November so his total for the year should be 185 + 172 = 357.
In my current report it adds together all the rows. How do i get it to just pick one row of reported hours per month?
Thanks

Answer 1

There's not a set way to do this in SSRS.
Usually you would wrap your query in another query that uses ROW_NUMBER and group by months. Then only add the hours if the row_numnber = 1.
How do I use ROW_NUMBER()?
Unfortunately that's not always possible. I wrote some code to add up unique records based on another field. I made it to get check amounts for various vendors.
For the expression, you would use:
=Code.SUMVendors(Report_Month & "|" & Fields!Reported_Hours.Value)
Add the Visual BASIC to the CODE of the report:
FUNCTION SUMVendors(BYVAL ITEMS AS OBJECT()) AS DECIMAL
'Returns Sum of unique vendors. Use as Code.SUMVendors(Vendor & "|" & Amount)
IF ITEMS IS NOTHING THEN
RETURN NOTHING
GOTO EXITSUB
END IF
DIM TEMP AS STRING
DIM VENDORS AS STRING = ""
DIM VENDOR AS STRING = ""
DIM VALUE AS DECIMAL
FOR EACH ITEM AS OBJECT IN ITEMS
TEMP = CONVERT.TOSTRING(ITEM)
VENDOR = "|" & LEFT(TEMP, InStr(TEMP, "|"))
VALUE = CDEC(MID(TEMP, InStr(TEMP, "|") + 1, LEN(TEMP)))
IF InStr(VENDORS, VENDOR) = 0 Then
VENDORS = VENDORS + VENDOR
SUMVendors = SUMVendors + VALUE
End If
NEXT
EXITSUB:
END FUNCTION