How can the performance of SQL queries in a database be improved?

To improve SQL query performance, the following methods can be used:

• Indexing — creating indexes on columns frequently used in WHERE and JOIN conditions.
• Query optimization — avoid SELECT *, use only necessary fields.
• Using prepared statements for recurring queries.
• Normalization and denormalization of data — balancing redundancy and access speed.
• Caching results — if data does not change often.
• Execution plan analysis (EXPLAIN) — identifying bottlenecks.

Example of creating an index:

CREATE INDEX idx_user_email ON users(email);

This will speed up user searches by email.