"Matheus Alcantara" <matheusssil...@gmail.com> writes: > You're right — semantically, using QUALIFY is equivalent to wrapping the > query in a subquery and applying a WHERE clause to the result. The main > motivation here is to provide a more ergonomic and readable syntax.
> While I understand the hesitation around introducing another keyword > that effectively acts like WHERE at a different stage, I believe QUALIFY > improves clarity in many use cases, by avoiding the boilerplate and > visual noise of nested subqueries making it easier to write and reason > about. There are concrete reasons not to do this until/unless it becomes standardized: * If the syntax is like WHERE, there will be no way to do it without making QUALIFY a fully-reserved word. That will inevitably break more than zero applications. It's a lot easier to justify that sort of breakage if we can say "QUALIFY is reserved according to SQL:20xx, so don't blame us". * I'm not exactly convinced that the committee would standardize it just like this. For one thing, QUALIFY is not even the right part of speech: it's a verb, and thus more fit to be a primary statement keyword. What you need here is an adverb (I think ... been a long time since high school English, but my dictionary says WHERE is an adverb). Maybe they'd be persuaded to do what the existing implementations did, but I wouldn't be at all surprised if they choose a different keyword. regards, tom lane