+1 That's a great proposal, Timo. I like the proposed simplified syntax. Also, being able to convert from or to a changelog is a really nice to have.
Gustavo On 2025/03/21 13:23:37 Timo Walther wrote: > Hi everyone, > > I would like to start a discussion about FLIP-517: Better Handling of > Dynamic Table Primitives with PTFs [1]. > > In the past months, I have spent a significant amount of time with SQL > semantics and the SQL standard around PTFs, when designing and > implementing FLIP-440 [2]. For those of you that have not taken a look > into the standard, the concept of Polymorphic Table Functions (PTF) > enables syntax for implementing custom SQL operators. In my opinion, > they are kind of a revolution in the SQL language. PTFs can take scalar > values, tables, models (in Flink), and column lists as arguments. With > these primitives, we can further evolve shortcomings in the Flink SQL > language by leveraging syntax and semantics. > > I would like introduce a couple of built-in PTFs with the goal to make > the handling of dynamic tables easier for users. Once users understand > how a PTF works, they can easily select from a list of functions to > approach a table for snapshots, changelogs, or searching. > > The FLIP proposes: > > SNAPSHOT() > SEARCH_KEY() > TO_CHANGELOG() > FROM_CHANGELOG() > > I'm aware that this is a delicate topic, and might lead to controversial > discussions. I hope with concise naming and syntax the benefit over the > existing syntax becomes clear. > > There are more useful PTFs to come, but those are the ones that I > currently see as the most fundamental ones to tell a round story around > Flink SQL. > > Looking forward to your feedback. > > Thanks, > Timo > > [1] > https://cwiki.apache.org/confluence/display/FLINK/FLIP-517%3A+Better+Handling+of+Dynamic+Table+Primitives+with+PTFs > [2] > https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=298781093 >
