HAVING for filtered groups

Concepts covered: sqlHaving

Understanding HAVING Why We Need HAVING Consider this question: "Which regions have more than 100 orders?" Groups are formed first, then the count threshold is applied. North (4 orders) and South (3 orders) pass the filter, while East (1 order) is eliminated entirely. HAVING Examples This finds highly-rated products with enough reviews to be statistically meaningful. Both conditions must be true: at least 10 reviews AND average rating of 4.0 or higher. Practical Patterns WHERE vs HAVING Execution Order

About This Interactive Section

This section is part of the Aggregating: Beginner lesson on DataDriven, a free data engineering interview prep platform. Each section includes explanations, worked examples, and hands-on code challenges that execute in real time. SQL queries run against a live PostgreSQL database. Python runs in a sandboxed Docker container. Data modeling problems validate against interactive schema canvases. All content is framed around what data engineering interviewers actually test at companies like Meta, Google, Amazon, Netflix, Stripe, and Databricks.

How DataDriven Lessons Work

DataDriven combines four interview rounds (SQL, Python, Data Modeling, Pipeline Architecture) with adaptive difficulty and spaced repetition. Easy problems get harder as you improve. Weak concepts resurface until you master them. Your readiness score tracks progress across every topic interviewers test. Every lesson section ends with problems you solve by writing and running real code, not by picking multiple-choice answers.