I assume Order Details[Order ID] is the problem. I think in this expression [Order ID] is not a key of this table of Order Details, but refer to the ID of the parent table, am i right?
If so, make sure to put key fields in stead of [Order ID]
Could you double check the key field name of Order Details?
@Phil_Waite Your SELECT is not filtering by Order ID. Its selecting Order ID but not filtering by it.
Add into the AND() function:
[Order ID] = [_THISROW].[Order ID].
Also, is [Order Status] on the “Order Details” table? If so, you are good. If its on the order table then you’ll want to update that part of the expression to: