Oracle Database Certification QUESTIONS AND
ANSWERS | VERIFIED AND WELL DETAILED
ANSWERS | PLUS RATIONALES | GUARANTEED PASS
| LATEST EXAM UPDATE | EXAM PREP | STUDY
GUIDE | PRACTICE TEST
,Section 1: SQL Fundamentals (Q1–Q25)
Q1. Which SQL statement is used to retrieve data from a table?
A) SELECT B) GET C) FETCH D) RETRIEVE
Answer: A
Rationale: SELECT is the only DML statement for querying data. GET/FETCH/RETRIEVE are not standalone
Oracle SQL statements (FETCH is a clause within SELECT).
Q2. Which clause filters rows before grouping?
A) HAVING B) WHERE C) GROUP BY D) ORDER BY
Answer: B
Rationale: WHERE filters individual rows before aggregation. HAVING filters after GROUP BY.
,Q3. What does `SELECT DISTINCT dept_id FROM employees;` return?
A) All rows B) Unique department IDs C) Count of departments D) Sorted rows
Answer: B
Rationale: DISTINCT eliminates duplicate rows from the result set.
Q4. Which operator checks for NULL?
A) = NULL B) IS NULL C) == NULL D) NULL()
Answer: B
Rationale: NULL cannot be compared with `=`; IS NULL / IS NOT NULL are the correct predicates.
Q5. What is the result of `SELECT 5/0 FROM dual;`?
A) 0 B) NULL C) Error D) Infinity
Answer: C
Rationale: Division by zero raises ORA-01476. Only NULL arithmetic returns NULL.
Q6. Which function returns the current date and time?
A) SYSDATE B) SYSTIMESTAMP C) CURRENT_DATE D) All of the above
Answer: D
, Rationale: SYSDATE (date), SYSTIMESTAMP (timestamp with TZ), CURRENT_DATE (session TZ) all return
current date/time.
Q7. `NVL(NULL, 'X')` returns:
A) NULL B) 'X' C) Error D) ''
Answer: B
Rationale: NVL replaces NULL with the second argument.
Q8. Which join returns rows matching in both tables only?
A) LEFT OUTER B) RIGHT OUTER C) INNER D) FULL OUTER
Answer: C
Rationale: INNER JOIN returns only matching rows from both tables.
Q9. Which is NOT a valid Oracle data type?
A) VARCHAR2 B) NUMBER C) STRING D) DATE
Answer: C
Rationale: Oracle has no STRING type; use VARCHAR2/CHAR.
ANSWERS | VERIFIED AND WELL DETAILED
ANSWERS | PLUS RATIONALES | GUARANTEED PASS
| LATEST EXAM UPDATE | EXAM PREP | STUDY
GUIDE | PRACTICE TEST
,Section 1: SQL Fundamentals (Q1–Q25)
Q1. Which SQL statement is used to retrieve data from a table?
A) SELECT B) GET C) FETCH D) RETRIEVE
Answer: A
Rationale: SELECT is the only DML statement for querying data. GET/FETCH/RETRIEVE are not standalone
Oracle SQL statements (FETCH is a clause within SELECT).
Q2. Which clause filters rows before grouping?
A) HAVING B) WHERE C) GROUP BY D) ORDER BY
Answer: B
Rationale: WHERE filters individual rows before aggregation. HAVING filters after GROUP BY.
,Q3. What does `SELECT DISTINCT dept_id FROM employees;` return?
A) All rows B) Unique department IDs C) Count of departments D) Sorted rows
Answer: B
Rationale: DISTINCT eliminates duplicate rows from the result set.
Q4. Which operator checks for NULL?
A) = NULL B) IS NULL C) == NULL D) NULL()
Answer: B
Rationale: NULL cannot be compared with `=`; IS NULL / IS NOT NULL are the correct predicates.
Q5. What is the result of `SELECT 5/0 FROM dual;`?
A) 0 B) NULL C) Error D) Infinity
Answer: C
Rationale: Division by zero raises ORA-01476. Only NULL arithmetic returns NULL.
Q6. Which function returns the current date and time?
A) SYSDATE B) SYSTIMESTAMP C) CURRENT_DATE D) All of the above
Answer: D
, Rationale: SYSDATE (date), SYSTIMESTAMP (timestamp with TZ), CURRENT_DATE (session TZ) all return
current date/time.
Q7. `NVL(NULL, 'X')` returns:
A) NULL B) 'X' C) Error D) ''
Answer: B
Rationale: NVL replaces NULL with the second argument.
Q8. Which join returns rows matching in both tables only?
A) LEFT OUTER B) RIGHT OUTER C) INNER D) FULL OUTER
Answer: C
Rationale: INNER JOIN returns only matching rows from both tables.
Q9. Which is NOT a valid Oracle data type?
A) VARCHAR2 B) NUMBER C) STRING D) DATE
Answer: C
Rationale: Oracle has no STRING type; use VARCHAR2/CHAR.
