Oracle Database 12c: SQL Fundamentals — Question 21

Evaluate the following SQL statement:
SQL> SELECT cust_id, cust_last_name "Last Name"

FROM customers -

WHERE country_id = 10 -

UNION -
SELECT cust_id CUST_NO, cust_last_name

FROM customers -
WHERE country_id = 30;
Which ORDER BY clause are valid for the above query? (Choose all that apply.)

Answer options

• A. ORDER BY 2, 1
• B. ORDER BY CUST_NO
• C. ORDER BY 2, cust_id
• D. ORDER BY "CUST_NO"
• E. ORDER BY "Last Name"

Correct answer: A, C, E

Explanation

The correct answers are A, C, and E because they reference valid column positions or aliases in the result set of the UNION query. Option B is incorrect as it uses an alias that is not defined in the first SELECT statement. Option D is also incorrect since it uses the alias in a way that does not match the column names in the final result set.