Hi,
Now You have Table : Vehicles, Months, Fuel_Bill, Lubi_Bill
I have one best idea to do this.
Now these tables are related let me consider Vehicles Table have the Collection of various Vehicles. and each vehicle will have a unique id which is the primary key.
secondly ill give u an example
vehicle table--Columns: VehicleID, Name, Model, Year....etc
Months--- MonthID, Month int(10), year int (10)
fuel_bill-- FuelID, VehicleID, MOnthID, ....etc
now what you are going to do is..
select * from fuel_bill FB
left outer join Vehicles V on V.VehicleID = FB.VehicleID
left outer join months m oh m.monthid = fb.monthid
where m.month = '1' and m.year = '2014'
this is just an example modify it with ur database
Now get this datasource and bind it to the datagridview.
Happy Programming.