MySQL + SQL · Lesson 92
Query Optimization in MySQL
Why Optimize?
As data grows, slow queries hurt. Optimization makes queries run faster using indexes and better SQL.
Key Tips
- Add indexes on columns used in WHERE and JOIN.
- Select only needed columns, not
SELECT *. - Avoid functions on indexed columns in WHERE (e.g.
WHERE YEAR(d)=2026skips the index). - Use
EXPLAINto see how a query runs. - Filter early with WHERE before joining.
Summary
- Optimize with indexes, fewer columns, and index-friendly WHERE.
- Use EXPLAIN to find slow spots.