What are the techniques for query optimization?

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Accepted Answer

Query optimization techniques enhance database performance by improving the efficiency of SQL queries.

Use indexing: Create indexes on frequently queried columns to speed up data retrieval. Example: Indexing a 'customer_id' column in a sales table.
Analyze query execution plans: Use tools like EXPLAIN to understand how queries are executed and identify bottlenecks.
Avoid SELECT *: Specify only the columns needed in the SELECT statement to reduce data transfer. Example: SELECT name, age FROM users.
Limit result sets: Use WHERE clauses to filter results and reduce the amount of data processed. Example: WHERE age > 30.
Optimize joins: Use INNER JOIN instead of OUTER JOIN when possible, and ensure that join conditions are indexed.

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