13. þ C. All set operators have equal precedence, so the precedence is
determined by the sequence in which they occur.
ý A, B, and D. A and B are incorrect because set operators have equal
precedence—though this may change in future releases. D is incorrect
because many set operators can be used in one compound query.
Bạn đang xem 13. - OCA OCP ORACLE DATABASE 11G A LL IN ONE EXAM GUIDE P59 PDF