SQL comments are used to explain and annotate code, making it easier for developers and teams to understand. Though comments don’t affect query execution, they play a vital role in documentation and debugging.
Time limit: 0
Quiz Summary
0 of 15 Questions completed
Questions:
Information
You have already completed the quiz before. Hence you can not start it again.
Which operator is used to check for NULL values in SQL?
Correct
Incorrect
Question 3 of 15
3. Question
What is the result of NULL = NULL in SQL?
Correct
Incorrect
Question 4 of 15
4. Question
How do you check if a column is not NULL?
Correct
Incorrect
Question 5 of 15
5. Question
Which of the following statements will return rows where salary is missing?
Correct
Incorrect
Question 6 of 15
6. Question
What does the COALESCE() function do in SQL?
Correct
Incorrect
Question 7 of 15
7. Question
What is the result of this query: SELECT COALESCE(NULL, NULL, ‘SQL’);?
Correct
Incorrect
Question 8 of 15
8. Question
Which function can be used to replace NULL with a custom value?
Correct
Incorrect
Question 9 of 15
9. Question
How does the COUNT() function treat NULLs?
Correct
Incorrect
Question 10 of 15
10. Question
What is returned by: SELECT COUNT(*) FROM employees;
Correct
Incorrect
Question 11 of 15
11. Question
In SQL, which comparison involving NULL returns TRUE?
Correct
Incorrect
Question 12 of 15
12. Question
Which of the following will return 0 if the column contains NULL?
Correct
Incorrect
Question 13 of 15
13. Question
What is the default behavior of GROUP BY when NULLs are present?
Correct
Incorrect
Question 14 of 15
14. Question
What happens when NULL is used in an arithmetic expression?
Correct
Incorrect
Question 15 of 15
15. Question
Which function helps to avoid NULL-related issues in aggregate calculations?
Correct
Incorrect
Summary
This quiz on SQL Comments reinforces best practices for using single-line and multi-line comments effectively in SQL. Ideal for beginners, professionals, and anyone writing maintainable SQL code.
At QuizOrbit, our team specializes in fun, informative quizzes across topics like general knowledge, technology, and entertainment. Boost your knowledge with our expert-designed quizzes.