Min Date for a detail

Hello everyone,

I was wondering if I could get your guys help. I have been stuck on this issue for quite some time and not sure if I can find a solution out there. So I have a merged between two data sources. BW and MS-SQL. For that reason if I use a date I have to do a Dimension as a detail. So my 2 questions are

1) Is there a way to take a min of detail dimension

2) I have two dates but only want the lowest how should I go about this?

Below is a screenshot

Thanks,

Scottie