Here are 10 more MySQL MCQs for UGC NET, SET, EMRS, KVS, ISRO, and Assistant Professor exams.
11. What is the purpose of the HAVING clause in MySQL?
A) It filters records before grouping
B) It filters records after grouping
C) It is used to rename columns
D) It is used to join tables
Answer: B) It filters records after grouping
12. Which MySQL function is used to count the number of rows in a table?
A) COUNT()
B) SUM()
C) TOTAL()
D) NUMBER()
Answer: A) COUNT()
13. What does the FOREIGN KEY constraint do in MySQL?
A) Ensures unique values in a column
B) Links a column to a primary key in another table
C) Automatically increments a column value
D) Restricts NULL values in a column
Answer: B) Links a column to a primary key in another table
14. Which command is used to create a backup of a MySQL database?
A) BACKUP DATABASE
B) SAVE DATABASE
C) mysqldump
D) EXPORT DATABASE
Answer: C) mysqldump
15. Which MySQL JOIN returns only matching rows from both tables?
A) LEFT JOIN
B) RIGHT JOIN
C) INNER JOIN
D) FULL JOIN
Answer: C) INNER JOIN
16. How can you change the structure of an existing MySQL table?
A) MODIFY TABLE
B) ALTER TABLE
C) UPDATE TABLE
D) CHANGE TABLE
Answer: B) ALTER TABLE
17. What is the maximum length of a VARCHAR column in MySQL?
A) 255
B) 512
C) 65535
D) 16384
Answer: C) 65535 (depends on row size)
18. What will happen if you use the DROP TABLE command in MySQL?
A) It will remove the table but keep the data
B) It will delete all rows but keep the table structure
C) It will permanently remove the table and its data
D) It will disable the table temporarily
Answer: C) It will permanently remove the table and its data
19. Which MySQL statement is used to retrieve unique records from a table?
A) SELECT UNIQUE
B) SELECT DISTINCT
C) SELECT FILTER
D) SELECT DIFFERENT
Answer: B) SELECT DISTINCT
20. What does the GROUP BY clause do in MySQL?
A) It sorts the data in ascending order
B) It groups records that have the same values in specified columns
C) It deletes duplicate rows from a table
D) It updates multiple records at once
Answer: B) It groups records that have the same values in specified columns
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