Q:

Sum From Lookup SSRS Reporting services

If i take a 4 day period it only shows capacity from the latest day, but I need to show the total capacity over 4 days.  I try to sum the capacity wich is a lookup that looks like this:
=Lookup(Fields!ID.Value,Fields!Name. Value,Fields!capacity. Value, "table_1")

It does not work if I just add a Sum() in the beginning and I've tried to solve it with Code. Lookup_Sum but lookup_Sum gets red. 
This is what I am trying to accomplish:

How can I do that? 

A:

Count Capacity in the QUERY as total Capacity

