OK. RowFilter applies to tables columns but still yet you can do same with Select() and get rows[] at once,no? Again, best of my knowledge, same issue applies.
RowFilter is a property of the datatable and select() is also a method of the datatable. So they'll only operate on columns in that specific table.
If you try to issue a myTable.Select( " myothertable.mydescript = 'something' "), you'll likely get some type of error that "myothertable.mydescript" isn't part of mytable, even if a relation has been defined.
I just did a test as a sanity check, and it errored out, the way I would have expected. (Unless someone is aware of some other syntax or capability...)
But you've given me a few things to think about for later, so again, thanks.
Kevin