With Oracle AI Database 23.26.2, Oracle introduced the new JOIN TO ONE syntax. As it happened, just a few weeks later, I was teaching an Oracle 26ai course for data warehouse developers, and we actually managed to take a first look at this brand-new feature. We found it interesting and promising – but it also immediately raised some critical questions. Our conclusion was clear: this deserves a closer look. And that is exactly what this blog post is about.