Tag Archives: Subquery
CTEs vs Subqueries in SQL: What’s the Difference and When to Use Them?
What happens when a SQL query becomes too long or hard to follow?> It gets confusing> Difficult to debug> Hard to maintain or extend Use Subqueries or Common Table Expressions (CTEs) to break down the logic and improve readability. What is a Subquery? A subquery is a query inside another query.Below is a query which shows customers whose remaining amount is above the average. What is a CTE (Common Table Expression)? A CTE is a temporary result set you can reference in a main query.It starts with the WITH keyword and improves readability, especially with multi-step logic. To Conclude: Subqueries Advantages Disadvantages Quick and easy for simple filtering. Harder to read when nested. Good for one-off checks. Redundancy if used multiple times (no reuse). CTEs (Common Table Expressions) Advantages Disadvantages Clean, readable SQL for complex queries. May be slightly slower in some databases. Can be recursive. Not supported in old SQL engines. Both subqueries and CTEs help you write better SQL but choosing the right one depends on your needs. We hope you found this blog useful, and if you would like to discuss anything, you can reach out to us at transform@cloudfonts.com
