Tell us about your experience analyzing and optimizing SQL query performance.

In my practice of analyzing and optimizing SQL queries, I usually start by examining the execution plan (EXPLAIN PLAN) to understand which operations take the most time.

Main optimization steps:

• Indexing: adding or adjusting indexes to speed up searches.
• Rewriting queries: simplifying complex JOINs or subqueries.
• Using parameterized queries for plan reuse.
• Limiting the result set: adding WHERE and LIMIT to reduce data volume.

Optimization example:

Before:

SELECT * FROM Orders o JOIN Customers c ON o.CustomerId = c.Id WHERE c.Name LIKE '%Smith%'

After:

CREATE INDEX idx_customers_name ON Customers(Name);

SELECT o.* FROM Orders o JOIN Customers c ON o.CustomerId = c.Id WHERE c.Name LIKE 'Smith%'

Here, an index is added and the filter is modified to use the index effectively.