This is not quite a MS Office question, is it?
Nevertheless, there are no simple yes/no answer to this. If you got a typical query, try it out in both SAS and Oracle.
To look behind the curtains a bit, you could use _method option in Proc SQL for SAS joins. MESGLEVEL=I will tell you if index is used for join optimization. debug=',,,D' sastraceloc=SASLOG will give you the Oracle SQL when doing implicit SQL pass.tru using LIBNAME ORACLE.