SSRS Filter with a different column from a different dataset

Question

I want to filter my column, let's call it AllStudentID from dataset1 with another column from a different datset.

Dataset1 had many column such as AllStudentID, Class, Time, Location. Dataset2 has other columns but i'm focused on a similar column called OnCampusID.

I've tried looking into using a filter but since the report itself has the columns from Dataset1, i run into an issue where if I select the column in dataset2, it always gives a First(OnCampusID). And I don't want that.

I looked into IIF() but again, i'm using a column from a different datset plus if let's say that they are NOT equal, I don't want to display anything, instead of putting something there. I know that you have to put a result if true and a result if false. If I"m thinking of it in terms of SQL statements, it's like having a WHERE clause WHERE AllStudentID=OnCampusID.

I tried running a Parameter but I don't want the select part on the top but rather have the report filtered already.

Am I missing something? I know it has to be simple.

Mind you, the following example above is just an example i made up, not the real thing.

Answer 1

Assuming that each OnCampusID only appears once in Dataset2 then you can do a Lookup expression to filter it:

=IIF(IsNothing(Lookup(Fields!AllStudentID.Value, Fields!OnCampusID.Value, Fields!OnCampusID.Value, "Dataset2")), False, True)

If OnCampusID appears more than once in Dataset2 then do the same thing using LookupSet .

To get the graduate field from Dataset2 just to a Lookup in the Value of the cell, like so:

=Lookup(Fields!AllStudentID.Value, Fields!OnCampusID.Value, Fields!Graduate.Value, "Dataset2")