For those aiming for junior developer or DBA roles, SQL is a crucial skill. MySQL, in particular, is commonly used in many companies and features prominently in interviews. This article outlines key MySQL interview questions, covering basic commands, definitions, and database operations. Whether it’s your first interview or your fifth, reviewing these SQL fundamentals can help you approach questions with confidence and clarity.
Key MySQL Interview Questions and Common Topics
What are DDL statements?
Data Definition Language statements define database structures using CREATE, ALTER, DROP.
What is DML, and what are some examples?
Data Manipulation Language (DML) includes commands for managing data using INSERT, SELECT, UPDATE and DELETE.
Explain indexing in MySQL.
Indexes speed up data retrieval, with B-tree being the default type in MySQL.
Name MySQL’s primary storage engines.
MySQL supports several storage engines.
InnoDB – Default storage engine, supports transactions.
MEMORY – Data stored in RAM, fast but temporary.
CSV – Handles CSV data directly.
How to check your MySQL version?
Run the following command to see your version.
SELECT version();
How do you add a new column?
To add columns, run this query.
ALTER TABLE your_table ADD COLUMN column_name DATATYPE;
How do you rename a table?
The command to rename a table is as follows.
RENAME TABLE old_table TO new_table;
What is the purpose of a primary key?
A primary key uniquely identifies records in a table, often with auto-increment.
Additional questions
How do you delete all rows without deleting the table?
Use TRUNCATE to empty the table but keep its structure.
How can you create a new MySQL user?
CREATE USER 'user'@'localhost' IDENTIFIED BY 'password';
How do you join tables to retrieve data?
Use JOIN statements to pull data from related tables:
SELECT columns
FROM table1 INNER JOIN table2 ON table1.col = table2.col;
What’s the default MySQL port?
The default port for MySQL is 3306.
Conclusion
By studying these common MySQL interview questions and SQL fundamentals, you can approach your next interview with confidence. From data handling to table structures, these basics will help you make a solid impression. Read the article SQL Interview Questions (MySQL): Part 1 to dive deeper.