6 Examples of Correlated Subqueries in SQL

The correlated subquery is one of the interesting but tricky concept to master in SQL. It's like recursion in computer science, which many developer struggle to understand and apply, but it's a such nice technique that I believe every programmer should learn and master. It took me long time to understand and master this technique and solving SQL queries which I am going to share with you today, played a huge role in learning correlated subqueries better. Sometime, you can solve a problem easily by using correlated subquery like the Nth highest salary problem, which is quite easy to solve using correlated subquery but difficult otherwise.