On Mon, 21 Jul 2025, 18:31 Tom Lane, <t...@sss.pgh.pa.us> wrote: > "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. >
I know we're not bikeshedding, but the word REFINE might be more appropriate. Thom >
