sql - how to use a composite key with the IN keyword in MS Access -

I want to write the following (pseudo) SQL statement in MS Access:

  Select MyTable From where to (A, B) (choose from A, B, MyTable);  

I tried that but got the complaint "You have written a subkey that can return more than one field without using the EXISTS reserved word in the FROM section of the main query."

I appreciate any feedback.

You can use an internal insert as a filter:

T1.a Select c from the MyTable t1 internal on = t2.a and t1.b = t2.b

Select c (Choose other tables from different A, B ) (I'm assuming that you have two tables because the query does not matter much to a table. Of course, all the combinations of A and B in Table 1 will be in "too" in Table 1.)