MySQL Mastery: Advanced Interview Questions for 2025 Quiz

1. Understanding Joins

   In the context of SQL joins, which JOIN type will always return all records from the left table along with matched records from the right table, with NULLs for unmatched rows from the right table? For example, given tables A and B, and A has rows with no match in B.

   1. A) LEFT JOIN
   2. B) INNER JOIN
   3. C) RIGHT JOIN
   4. D) CROSS JOIN
   5. E) LEFF JOIN

2. Transactional Storage Engines

   Which MySQL storage engine supports row-level locking and transaction-safe operations, including atomicity, consistency, isolation, and durability (ACID) compliance? Example: Ensuring data consistency on concurrent writes.

   1. A) InnoDB
   2. B) MyISAM
   3. C) MEMORY
   4. D) CSV
   5. E) InnoBB

3. Query Performance Tools

   Which MySQL statement will display the execution plan for a SELECT query, helping you analyze how tables are accessed and joined? For example, you want to diagnose a slow query.

   1. A) EXPLAIN
   2. B) ANALYZE
   3. C) INTERPRET
   4. D) SHOW QUERY
   5. E) EXPLAN

4. SQL Aggregation Clauses

   Which clause should be used to filter results after aggregation, such as filtering records based on the count of orders per user, as opposed to filtering rows before aggregation?

   1. A) HAVING
   2. B) GROUP BY
   3. C) WHERE
   4. D) LIMIT
   5. E) HVAING

5. Character Data Types

   If you want to store fixed-length character strings in MySQL for fast access and space is not a concern (e.g., storing 8-character codes), which column type should be used?

   1. A) CHAR
   2. B) VARCHAR
   3. C) TEXT
   4. D) CHARR
   5. E) VARCAR