Quiz for FULL OUTER JOIN

Q1: What does FULL OUTER JOIN return?

A. Only matching rows B. All unmatched rows only C. All rows from both tables, matched and unmatched D. Only NULL values

Q2: Which clause is used to perform a FULL OUTER JOIN in SQL?

A. FULL OUTER JOIN B. OUTER JOIN C. FULL JOIN D. JOIN

Q3: Which SQL databases do not support FULL OUTER JOIN directly?

A. MySQL B. PostgreSQL C. SQL Server D. Oracle

Q4: How can FULL OUTER JOIN be simulated in MySQL?

A. Using UNION of LEFT and RIGHT JOIN B. Using INNER JOIN C. Using CROSS JOIN D. Using only LEFT JOIN

Q5: What is the result of FULL OUTER JOIN when there is no match between two tables?

A. Empty result set B. Rows from both tables with NULLs C. Only matching rows D. Only unmatched rows

Q6: Which join returns all rows from two tables and fills in NULLs for missing matches?

A. INNER JOIN B. LEFT JOIN C. RIGHT JOIN D. FULL OUTER JOIN

Q7: If Table A has 4 rows and Table B has 6 rows, how many rows could a FULL OUTER JOIN return at most?

A. 4 B. 6 C. 10 D. 24

Q8: In FULL OUTER JOIN, unmatched columns are filled with?

A. Zeros B. Empty strings C. NULLs D. Default values

Q9: Which keyword combination can simulate FULL OUTER JOIN in MySQL?

A. LEFT JOIN + RIGHT JOIN B. LEFT JOIN + CROSS JOIN C. INNER JOIN + OUTER JOIN D. CROSS JOIN + UNION

Q10: Can FULL OUTER JOIN be used with WHERE clause?

A. Yes B. No C. Only with JOIN D. Only with GROUP BY

Q11: Which function helps filter NULLs after FULL OUTER JOIN?

A. IFNULL() B. ISNULL() C. COALESCE() D. All of the above

Q12: When combining rows with FULL OUTER JOIN, which condition identifies matching rows?

A. Primary Key B. Foreign Key C. Common column values D. All columns must match

Q13: Which join type will return unmatched rows from both tables?

A. INNER JOIN B. FULL OUTER JOIN C. LEFT JOIN D. RIGHT JOIN

Q14: Which SQL clause can be used with FULL OUTER JOIN to group results?

A. GROUP BY B. ORDER BY C. HAVING D. All of the above

Q15: What happens if there are multiple matches in FULL OUTER JOIN?

A. Only one is returned B. NULL is returned C. All combinations are returned D. Join fails

Q16: Which join type produces the largest result set?

A. INNER JOIN B. FULL OUTER JOIN C. LEFT JOIN D. RIGHT JOIN

Q17: What does the FULL OUTER JOIN keyword look like in standard SQL syntax?

A. JOIN FULL OUTER B. OUTER FULL JOIN C. FULL OUTER JOIN D. JOIN OUTER FULL

Q18: What is a typical use case of FULL OUTER JOIN?

A. To find matching rows only B. To compare two tables and find all records C. To delete unmatched records D. To update one table from another

Q19: Is FULL OUTER JOIN part of ANSI SQL standard?

A. Yes B. No C. Only in Oracle D. Only in SQL Server

Q20: What is needed to simulate FULL OUTER JOIN in MySQL?

A. UNION of LEFT and RIGHT JOINs B. Only RIGHT JOIN C. Multiple INNER JOINs D. UNION ALL of INNER JOINs