SQL Interview Prep for MySQL: Key Questions to Know

SQL interview questions frequently focus on MySQL for roles in database administration or backend development. If you’re targeting a junior role, it’s essential to understand the core MySQL commands and structures that commonly appear in interviews. Here’s a rundown of the most frequently asked SQL interview questions to help you prepare and make a great impression.

Common MySQL Interview Questions

Describe DDL statements.Data Definition Language (DDL) defines database structure with CREATE, ALTER and DROP.

What is DML, and what commands does it include?

Data Manipulation Language (DML) handles data in tables with INSERT, SELECT, UPDATE and DELETE.

What is an index, and what types exist in MySQL?

An index improves data retrieval speed. B-tree is the default index type.

Explain some storage engines in MySQL.

MySQL offers various storage engines:

• InnoDB – Default engine with transaction support.
• MEMORY – Fast but temporary storage.
• CSV – Manages CSV files.

How do you check the MySQL version?

SELECT version();

How do you add columns in MySQL?

Use ALTER TABLE:

ALTER TABLE table_name ADD COLUMN column_name DATATYPE;

What’s the syntax for renaming a table?

RENAME TABLE old_table TO new_table;

What’s the role of a primary key?

It uniquely identifies each table record and often auto-increments.

Additional Questions

How to delete all rows in a table?

Use TRUNCATE to clear data without altering structure.

How to add a MySQL user?

CREATE USER 'user'@'localhost' IDENTIFIED BY 'password';

How do you join tables in MySQL?

Use JOIN to pull data from multiple tables:

SELECT columns 
FROM table1 INNER JOIN table2 ON table1.col = table2.col;

What’s MySQL’s default port?

It’s 3306.

Conclusion

Mastering these essential SQL interview questions for MySQL can set you apart as a junior developer or DBA. Familiarizing yourself with core topics like DDL and DML statements, indexing, storage engines, and key SQL commands will prepare you for many of the scenarios you might encounter in interviews. By studying these questions and practicing them in a MySQL environment, you’ll strengthen your foundation and approach your interview with greater confidence.

For more comprehensive preparation, explore the complete article SQL Interview Questions (MySQL): Part 1.