These help test your theoretical understanding of MySQL.
Sample Questions:
Q1. Which command is used to remove all records from a table but not the structure?
- DROP TABLE
B. DELETE
C. TRUNCATE ✅
D. REMOVE
Q2. Which constraint ensures a column cannot contain NULL values?
- UNIQUE
B. DEFAULT
C. NOT NULL ✅
D. INDEX
Q3. Which command is used to create a new database in MySQL?
A. MAKE DATABASE
B. CREATE DB
C. NEW DATABASE
D. CREATE DATABASE ✅
Q4. What does the AUTO_INCREMENT attribute do?
A. Automatically updates column values
B. Increments string values
C. Generates unique numeric values ✅
D. Deletes duplicate entries
Q5. What is the default port for MySQL?
A. 80
B. 1433
C. 3306 ✅
D. 1521
Q6. Which MySQL statement is used to retrieve data?
A. FETCH
B. EXTRACT
C. GET
D. SELECT ✅
Q7. Which of the following is a valid data type in MySQL?
A. number
B. integer
C. INT ✅
D. num
Q8. Which keyword is used to filter rows?
A. GROUP BY
B. ORDER BY
C. WHERE ✅
D. SELECT
Q9. What is the result of: SELECT 3 + 5;
A. 8 ✅
B. 35
C. 53
D. NULL
Q10. VARCHAR(100) means:
A. Fixed 100 characters
B. Variable up to 100 characters ✅
C. Exactly 100 words
D. Integer limit
Q11. Which clause is used to remove duplicate rows?
A. REMOVE
B. GROUP BY
C. DISTINCT ✅
D. UNIQUE
Q12. Which statement is used to change a table structure?
A. CHANGE TABLE
B. MODIFY
C. ALTER TABLE ✅
D. RENAME
Q13. Which clause is used to sort records in SQL?
A. SORT
B. ORDER BY ✅
C. GROUP BY
D. RANK
Q14. Which of the following statements is used to delete a table completely?
A. REMOVE TABLE
B. DELETE TABLE
C. DROP TABLE ✅
D. ERASE
Q15. What is a FOREIGN KEY used for?
A. To encrypt data
B. To link records across tables ✅
C. To create indexes
D. To make a column unique
Q16. Which keyword is used to rename a column or table?
A. MODIFY
B. UPDATE
C. RENAME ✅
D. REPLACE
Q17. Which aggregate function is used to get the number of records?
A. TOTAL
B. COUNT ✅
C. SUM
D. LENGTH
Q18. Which operator is used to compare a value to a list of values?
A. LIKE
B. MATCHES
C. IN ✅
D. BETWEEN
Q19. What does NULL mean in MySQL?
A. 0
B. Blank
C. Unknown or missing value ✅
D. Empty string
Q20. Which clause is used after GROUP BY to filter groups?
A. WHERE
B. HAVING ✅
C. FILTER
D. SELECT
Q21. Which function returns the current date and time in MySQL?
A. TIME()
B. SYSDATE()
C. NOW() ✅
D. DATE()
Q22. What is a view in MySQL?
A. A stored function
B. A backup table
C. A virtual table ✅
D. A schema
Q23. Which command is used to back up a MySQL database?
A. mysqlbackup
B. mysql_export
C. mysqldump ✅
D. mysql_restore
Q24. Which function calculates average value?
A. MEAN
B. AVG ✅
C. AVERAGE
D. MID
Q25. What is the purpose of a trigger?
A. Manual insert
B. Generate key
C. Automatically execute on event ✅
D. Compile SQL
Q26. Which command will show all databases?
A. LIST DATABASES
B. GET DATABASES
C. SHOW DATABASES ✅
D. SHOW ALL
Q27. What is the result of ROUND(5.6789, 2)?
A. 5.6
B. 5.67
C. 5.68 ✅
D. 5.679
Q28. Which clause is used to limit the number of returned rows?
A. MAX
B. RANGE
C. LIMIT ✅
D. SIZE
Q29. A UNIQUE constraint:
A. Allows NULL and ensures no duplicates ✅
B. Prevents NULL and duplicates
C. Is same as PRIMARY KEY
D. Can only be used on strings
Q30. The keyword EXISTS is used for:
A. Checking table presence
B. Checking if a subquery returns any rows ✅
C. Joining tables
D. Checking schema
Q31. Which JOIN returns all records from both tables, matching where possible?
A. INNER JOIN
B. LEFT JOIN
C. FULL OUTER JOIN ✅
D. RIGHT JOIN
Q32. Which command revokes privileges from a user?
A. REVOKE ✅
B. DENY
C. REMOVE
D. BLOCK
Q33. Which MySQL engine supports transactions?
A. MyISAM
B. ARCHIVE
C. InnoDB ✅
D. MEMORY
Q34. What is the correct syntax to delete a column?
A. REMOVE COLUMN
B. DELETE COLUMN
C. ALTER TABLE table_name DROP COLUMN col_name; ✅
D. MODIFY COLUMN
Q35. What does SET autocommit = 0; do?
A. Enables backup
B. Prevents table deletion
C. Turns off automatic commit ✅
D. Starts replication
Q36. The LIKE operator is used for:
A. Arithmetic
B. Exact matching
C. Pattern matching ✅
D. JOINs
Q37. Which function gets the number of characters in a string?
A. LEN
B. COUNT
C. LENGTH ✅
D. CHARCOUNT
Q38. REPLACE INTO works like:
A. INSERT
B. INSERT + DELETE
C. UPSERT ✅
D. UPDATE
Q39. Which of these can be used inside a trigger?
A. COMMIT
B. ROLLBACK
C. INSERT ✅
D. SELECT INTO
Q40. GRANT SELECT ON db.* TO ‘user’@’localhost’;
A. Creates a user
B. Gives read access ✅
C. Drops a role
D. Denies write access
Q41. Which format is used for MySQL binary log?
A. JSON
B. CSV
C. BIN ✅
D. XML
Q42. Which command shows active connections?
A. SHOW USERS
B. SHOW PROCESSLIST ✅
C. CURRENT_USERS
D. SYSTEM STATUS
Q43. What is partitioning in MySQL?
A. Database design
B. Dividing tables into logical parts ✅
C. Normalization
D. Clustering
Q44. Which is not allowed inside a MySQL function?
A. SELECT
B. RETURN
C. UPDATE ✅
D. DECLARE
Q45. What is the difference between DELETE and TRUNCATE?
A. DELETE is faster
B. TRUNCATE logs individual rows
C. DELETE can be rolled back, TRUNCATE cannot ✅
D. TRUNCATE is DML
Q46. Which of the following is a DDL command?
A. INSERT
B. UPDATE
C. CREATE ✅
D. SELECT
Q47. What will this return: SELECT MOD(10, 3);
A. 3
B. 10
C. 1 ✅
D. 0
Q48. What does SHOW CREATE TABLE table_name; do?
A. Shows all rows
B. Recreates the table
C. Shows the SQL used to create the table ✅
D. Describes the table
Q49. Which MySQL statement is used to undo a transaction?
A. ROLLBACK ✅
B. STOP
C. CANCEL
D. EXIT
Q50. What is the default user in MySQL?
A. admin
B. mysql
C. user
D. root ✅