I am working with VB.Net in Visual Studio 2010, and I need to perform an unmatched query in LINQ, when two fields are included in the linking. What makes it tricky, is I only want to return records where one of the field matches, and the other does not.
I think it will make more sense if I lay out an example.
So this is an example of my Main Data Table:
And here is a sample of my Reference Table:
Basically, what I am looking for is new instances of records where the GroupID already exists in my Reference table, but the SubGroupID does not.
So, I would only expect to return one record, specifically:
because that is the only record where the GroupID already exists in my Reference Table, but the SubGroupID (of "SSS") does not.
Can someone help me come up with the LINQ code for this? BTW, this is not an Entity Framework, so I need to qualify the field types in my LINQ query code (they are both "Of String").