Help with a formula to search and add numbers together?


I am not sure if there is a formula to solve this problem. If there is, I am hoping someone can point me in the right direction.

I receive cases that have a specific number of hours to be worked. I have a table for the CASE LIST which has a field showing total number of hours assigned.

I have another table we can call WORK DAYS. Each work day will have an employee assigned, some notes and the number of hours worked. The two will be linked by a field CASE NAME.

I would like one field on the CASE LIST table to search all the entries on the WORK DAYS table, add up the hours on each record in that table that match the same CASE NAME and then subtract from the original assigned hours.

Is something like this possible? This is really the most important aspect I need to have out of this database. I appreciate any ideas! I am rather new to databases and although I have used spreadsheets, I am not sure if this kind of calculation is something I can even do.