How to check if dt.AsEnumerable is Null before copying it UIPATH

I am using

dt1.AsEnumerable().Where(Function(row) Not dt2.AsEnumerable(). Select(Function(r) r.Field(Of String)("Otsikko")).Any(Function(x) x = row.Field(Of String)("Otsikko"))). CopyToDataTable()

Which works perfectly until Both A and B columns match. This leads to situation when "CopyToDataTable()" has nothing to copy and provides error.

How can I add IF to check if the item I am trying to copy is empty. If its not empty I want it to Copy the datatable, if it is the query should move forward.

I am newbie to all this! So any help is appreciated.

Thank you on advance.

Lari