Nested Queries in SQL - Explained

Hello!!
Welcome to the new edition of Business Analytics Review!

Today, we’re exploring a fundamental yet powerful concept in SQL: nested queries, also known as subqueries. Whether you’re a beginner or an experienced database user, mastering nested queries can significantly enhance your ability to write complex and efficient SQL statements.

A nested query is a query embedded within another SQL query. The outer query uses the results of the inner query to perform its operations. This structure allows for more dynamic and powerful data retrieval, enabling you to perform complex operations that would be cumbersome with simple queries.

For example, consider a scenario where you want to find customers who have placed orders worth more than the average order value. Instead of calculating the average order value separately and manually filtering customers, you can nest a query that calculates the average directly within your main query