7. Some basic SQL query optimization techniques:

1. SELECT fields instead of using SELECT *
2. Avoid SELECT DISTINCT where possible
3. Create joins with INNER JOIN (not WHERE)
4. Use WHERE instead of HAVING to define filters
5. Use LIMIT to sample query results
6. Run your query during off-peak hours
7. Create index on very large tables (>1000000) rows
8. Choose group by over window functions
9. Use derived and temporary tables
10. Use materialized views instead of views
11. Avoid != or <> (not equal) operator
12. Minimize the number of subqueries

https://www.linkedin.com/posts/shaheershahzad_sql-sqlqueries-activity-6857958287493644288-FdjH/