Describe your experience with writing and optimizing SQL queries in your projects.

In my projects, I often wrote SQL queries for data selection, updating, and aggregation. To optimize queries, I used indexes, avoided redundant JOINs and subqueries, and tried to minimize the number of returned rows and columns.

For example, when working with large tables, I added indexes on fields involved in WHERE and JOIN conditions, which significantly sped up query execution. I also used EXPLAIN PLAN to analyze query execution plans and identify bottlenecks.

A simple optimized query example:

SELECT Id, Name FROM Users WHERE IsActive = 1 AND CreatedDate > '2023-01-01'

It is important that indexes exist on the IsActive and CreatedDate fields to ensure fast filtering. Additionally, I avoided SELECT * to prevent loading unnecessary data.