160 Must‑Know MySQL Interview Questions to Test Your Skills

MySQL is a common weak spot for many developers during interviews, so this article compiles 160 frequently asked MySQL interview questions to help readers review and strengthen their knowledge before the interview.

Sample Questions

1. What is SQL? Structured Query Language (SQL) is a database query language used for accessing, querying, updating, and managing relational database systems.

2. What is MySQL? MySQL is a relational database management system developed by MySQL AB (now owned by Oracle). It is one of the most popular RDBMSs, especially in web applications and Java enterprise development, because it is open‑source, free, and easy to scale.

3. Differences among MySQL, Oracle, and SQL Service

SQL Service runs only on Windows, while MySQL and Oracle are cross‑platform and support migration between systems.

MySQL is open‑source and free; SQL Service and Oracle require licensing fees.

In terms of size, MySQL is the smallest, SQL Service is medium, and Oracle is the largest.

Oracle handles high concurrency and large traffic better; MySQL’s performance under heavy load often requires clustering or caching.

Oracle supports fine‑grained user permissions; MySQL grants full access to any user with login rights.

Installation footprint: MySQL occupies a few hundred megabytes, whereas Oracle requires several gigabytes and consumes significantly more memory.

4. What are the three normal forms?

First Normal Form (1NF): each column holds atomic values that cannot be further divided.

Second Normal Form (2NF): based on 1NF, non‑key columns must be fully dependent on the whole primary key, not just part of it.

Third Normal Form (3NF): based on 2NF, non‑key columns depend only on the primary key and not on other non‑key columns.

When designing a database schema, it is advisable to follow the three normal forms unless there is a justified reason—such as performance considerations—to deviate.

5. Which MySQL privilege tables exist? user: stores global‑level user account information. db: records database‑level permissions for each account. table_priv: records table‑level permissions. columns_priv: records column‑level permissions. host: works with db to control host‑specific database permissions and is not affected by GRANT / REVOKE statements.

The remainder of the 160 questions—including topics such as indexing, transaction isolation, stored procedures, performance tuning, and advanced query techniques—are compiled in a PDF that can be downloaded for free.

By reviewing these questions and their answers, readers can better prepare for MySQL‑related interview sections and increase their chances of success.