MySQL + SQL · Lesson 123
MySQL Interview Questions
Common MySQL Interview Questions
Practical MySQL/SQL questions often asked in interviews.
Questions & Answers
| Question | Short Answer |
|---|---|
| WHERE vs HAVING? | WHERE filters rows; HAVING filters groups. |
| INNER vs LEFT JOIN? | INNER = matches only; LEFT = all left rows + matches. |
| What is an index? | A structure that speeds up searches. |
| What is a view? | A saved query acting as a virtual table. |
| How to prevent SQL injection? | Use prepared statements. |
| InnoDB vs MyISAM? | InnoDB has transactions & foreign keys; MyISAM does not. |
Summary
- Master WHERE/HAVING, JOIN types, indexes, views, injection, engines.
- Back each answer with a one-line example.