The paper directly references PRQL and Kusto. The main goal here is to take lessons learned from earlier efforts and try and find a syntax that works inside and alongside the existing SQL grammar, rather than as a wholly separate language.
I've been following PRQL for some time now since it first got good traction on HN and I like it a lot, but I'm really hoping this pipe syntax from Google takes off for a couple of reasons:
1. Similar to what you mention, while I think PRQL is pretty easy to learn if you know SQL, it still "feels" like a brand new language. This piped SQL syntax immediately felt awesome to me - it mapped how my brain likes to think about queries (essentially putting data through a chain of sieves and transforms), but all my knowledge of SQL felt like it just transferred over as-is.
2. I feel like I'm old enough now to know that the most critical thing for adoption of new technologies that are incremental improvements over existing technologies is to make the upgrade path as easy as possible. I shouldn't have to overhaul everything at once, but I just want to be able to take in small pieces a chunk at a time. While not 100% the same thing, if you look at the famously abysmal uptake of things like IPv6 and the pain it takes to use ES module-only distributions from NPM, the biggest pain point was these technologies made you do "all or nothing" migrations - they didn't have an easy, simple way to get from point A to point B. The thing I like about this piped SQL syntax is that in a large, existing code base I could easily just start adding this in new queries, but I wouldn't really feel the need to overhaul everything at once. With PRQL I'd feel a lot less enthusiastic about using that in existing projects where I'd have a mix of SQL and PRQL.
It's wild that the enterprise and connected world has moved on from forcing COBOL compatibility for modern projects, but still insists on SQL compatibility.
