Sounds to me like you may need to use a calculation field.
You can create a calculation field that grabs min/max/last etc from a related table.
for example, if table 1 is Invoices and table 2 is invoice items and you have a relationship between them, you can create a calculation in table 1 called min(invoice items::date) to grab the lowest date via the relationship.
There are a lot of different calculations that work this way. There are also different ways to acheive what you're after, but this is a simple way that should get you the result you're after