I know this should be simple but I seem to be tying myself in knots trying to get this done.

Form1 has a list of week no's. ie 1,2,3,4,5 etc as type string (so they sort).

Form2 has a lookup to the week no's in Form1 as well as an errorName.

I want to count all the errors that have occurred in the last x number of weeks.

ie count of Form2 where week no is todays week no - 12. This would give me the total number of errors in the past 3 months.

Any help is much appreciated, thanks!