Combine two datatables in one datatable using select query

Question

Hello,

Can anybody help me please how to combine two datatables in one resulting datatable in the same dataset using select statement?

I made three select commands, the first two for filling the first two tables, and the third which combines them for filling a third datatable. These works fine when run in access.
But I don't know how to use the third, combining select command, to fill the third datatable in the dataset.

Then I want to use this third datatable for populating my Crystal Report.

If somebody has an idea, I would appreciate your help a lot.
Thanks in advance.