Oracle Database Administration I — Question 89

Which two queries execute successfully? (Choose two.)

Answer options

• A. SELECT NULLIF(NULL, 100) FROM DUAL;
• B. SELECT NULLIF(100, 'A') FROM DUAL;
• C. SELECT COALESCE(100, 'A') FROM DUAL;
• D. SELECT COALESCE(100, NULL, 200) FROM DUAL;
• E. SELECT NULLIF(100, 100) FROM DUAL;

Correct answer: D, E

Explanation

Option D executes successfully because COALESCE can handle NULL values and will return the first non-null value, which is 100. Option E also executes successfully because NULLIF returns NULL if the two arguments are equal, and since both are 100, it returns NULL. Options A, B, and C will fail due to incompatible data types or logic.