Quiz for NATURAL JOIN

Q1: What does NATURAL JOIN do?

A. Joins without any matching condition B. Joins using columns with the same name in both tables C. Only joins primary keys D. Joins all NULLs

Q2: What is a NATURAL JOIN in SQL?

A. A join that uses ON clause B. A join that compares all columns C. A join based on common column names D. A join using WHERE clause

Q3: Which clause is NOT needed in a NATURAL JOIN?

A. USING B. ON C. WHERE D. JOIN

Q4: What happens if there are no matching column names in a NATURAL JOIN?

A. It returns NULLs B. It performs a CROSS JOIN C. It throws an error D. It returns an empty result

Q5: NATURAL JOIN is equivalent to which of the following?

A. INNER JOIN using USING clause B. CROSS JOIN C. LEFT JOIN with ON D. RIGHT JOIN using WHERE

Q6: What is a drawback of NATURAL JOIN?

A. Can join on incorrect columns B. It is slow C. Requires subqueries D. Uses too much memory

Q7: Is column aliasing possible in NATURAL JOIN?

A. Yes, always B. Only for one table C. No D. Yes, with USING clause

Q8: Which of the following SQL statements uses NATURAL JOIN correctly?

A. SELECT * FROM A NATURAL JOIN B; B. SELECT * FROM A JOIN B; C. SELECT * FROM A, B; D. SELECT * FROM A RIGHT JOIN B;

Q9: In NATURAL JOIN, duplicate columns in result are:

A. Shown as is B. Merged into one C. Renamed automatically D. Removed completely

Q10: Can NATURAL JOIN be used on more than two tables?

A. Yes B. No C. Only with subquery D. Only with LEFT JOIN

Q11: Which join type avoids specifying join condition explicitly?

A. INNER JOIN B. LEFT JOIN C. NATURAL JOIN D. CROSS JOIN

Q12: Does NATURAL JOIN work with NULL values?

A. Yes, they are matched B. No, NULLs are excluded C. It throws error D. Only in PostgreSQL

Q13: What is a risk when using NATURAL JOIN?

A. Joining unrelated columns B. Low performance C. Slow sorting D. Data loss

Q14: When is NATURAL JOIN most suitable?

A. When joining on different columns B. When tables share column names C. When there is no key D. In data migration only

Q15: What happens to columns with same name in NATURAL JOIN?

A. One column is shown B. Both are shown C. Column is renamed D. Error occurs

Q16: Can NATURAL JOIN be used with WHERE clause?

A. No B. Yes C. Only if INNER JOIN D. Only if USING

Q17: Which database supports NATURAL JOIN?

A. Oracle B. MySQL C. PostgreSQL D. All of the above

Q18: Does NATURAL JOIN reduce query flexibility?

A. Yes B. No C. Only for LEFT JOIN D. Only for subqueries

Q19: What is output if NATURAL JOIN has no common columns?

A. Cartesian product B. Error C. No rows D. One NULL row

Q20: What is the main benefit of NATURAL JOIN?

A. Readable syntax B. Avoids duplicates C. No ON clause needed D. All of the above

Q21: Which is better for maintainability?

A. NATURAL JOIN B. INNER JOIN with ON C. RIGHT JOIN D. CROSS JOIN