← 🗃️ SQL Deep Dive24 / 25
Lesson 24 — EXISTS vs IN
Correlated filtering
EXISTS checks whether a related row exists, often faster than IN for big data.
Why it matters: picking the right one affects query speed.
Task
List users who have at least one order.
Keep going with SQL Deep Dive
Ready for more? These paid resources pick up where this lesson leaves off.
UdemyBestsellers
Top-rated SQL Deep Dive courses
Project-based SQL Deep Dive video courses — the perfect paid next step after these free lessons.
Browse on Udemy →AmazonReader picks
Best SQL Deep Dive books
Hand-picked SQL Deep Dive books to master the fundamentals offline.
See on Amazon →Some links on this page are affiliate links: we may earn a commission at no extra cost to you. We only recommend tools we believe are genuinely useful.