OCA Oracle Database SQL Certified Expert Exam Guide (Exam 1Z0-047)

12Using the Set Operators

CERTIFICATION OBJECTIVES

12.01 Describe Set Operators

12.02 Use a Set Operator to Combine Multiple Queries into a Single Query

12.03 Control the Order of Rows Returned

Two-Minute Drill

Q&A Self Test

This chapter describes the set operators in SQL. Set operators work with sets of output data from two or more SELECT statements. They combine standalone SELECT statements in ways that cannot be done with joins or other conventional methods in SQL.

Set operators are ideal for a variety of situations where a SELECT statement’s output can be combined with other data that isn’t necessarily related through a structured key relationship ...