Hey there - I've found my way here via Measures in SQL <https://dl.acm.org/doi/pdf/10.1145/3626246.3653374>. I'm a long time admirer of Calcite, but I'm not very familiar with internals - apologies if I stumble.
I work on Airbnb's Minerva <https://medium.com/airbnb-engineering/how-airbnb-achieved-metric-consistency-at-scale-f23cc53dea70> project, an internal semantic layer for star schemas. Measures in SQL is a wonderfully elegant idea, and I've started exploring if we can introduce them to our system. However, our users often write queries that span multiple tables/stars, requiring a drill across operation. Our system handles this by exposing a virtual table that pretends as if our entire semantic layer is a single, wide fact table. Incompatible measure/dimension combinations result in runtime errors. This need feels pretty common and a logical extension to some of Measures' strengths - making SQL more powerful and expressive for "top down" queries. I'm curious - are there plans to support measures that span multiple tables in Calcite? - Barak
