Complete PostgreSQL Course for Beginners - Stop Wasting Indexes: The #1 Rule for B-Tree in SQL #coding

Learn why B-Tree indexes work best on high-cardinality columns and how the wrong index can slow your SQL queries. Get this simple but powerful indexing rule right and boost performance instantly. 👉 Apply for my Live SQL Training here: https://www.dataprofy.com/sqltraining/ Indexing can make or break your SQL query performance. In this video, I explain the right way to use B-Tree indexes and why they should be applied only on high-cardinality columns—columns with many unique values like email_id or emp_id. These indexes help speed up searches, joins, and sorting, while low-cardinality columns like gender or status usually make the optimizer ignore the index and scan the table instead. I’ll also show you a clear example with dummy data so you can see exactly when a B-Tree index is effective and when it’s not. This small tip can save hours of execution time and is one of the most important lessons for anyone serious about SQL optimization. If you want to master SQL at a professional level, join my Live SQL Corporate Training starting 15th September. 👉 Apply here: https://www.dataprofy.com/sqltraining/