Select multiple columns

[Tragertt]

I am not sure sure how to do this or even if I can. 

I have a table named [Main] and another table named [Student Report]

I have another 2 tables that had to be broken up because of size, they are [Grades 1] and [Grades 2].

On the [Student Report] I have a field named [Grades] and what I would like to do is to return the value of  [Grades 1] or [Grades 2] if they have one. All students are either in table [Grades 1] or [Grades 2]. So I would like some code that would be select(main [Related Grades 1] or [Reated Grades 2], [Student ID = [_Thisrow].[Student ID]))

I have tried all variations I can think of and none work. Any Ideas?

[TeeSee1 · Accepted solution]

Couldn't you just add the resultant lists from the two tables?

SELECT(
 Grades 1[target col],
 [Student ID] = [_THISROW].[Student ID]
)
+
SELECT(
 Grades 2[target col],
 [Student ID] = [_THISROW].[Student ID]
)

[Tragertt]

That worked, thank you so much!