SQL query summation

Question

I have two tables

Unit

Unit_id
Unit_name
Unit_cost

Components

Component_id
Component_         


        

Answer 1

I think you want something like this:

select top (1) u.unit_name
from unit u join
     component c
     on c.unit_id = u.unit_id
group by u.unit_id, u.unit_name
order by sum(c.cost) desc;