Also, to generalize a bit: if a human is expected to read it, the way humans write should be able to be parsed by it. That's subjective, to a point, but it's an easy rule-of-thumb to remember. Trailing commas are so common that people have built workarounds for them. Therefore, they can be understood as "the way humans write". If you're writing a language that you still want to be readable by humans, you really should account for that. And, no shade for it not already being done. I'm just reiterating that there should be NO pushback to allowing trailing commas. It's a completely "common-sense" proposal.
The SQL standards committee is having none of it. I can tell you that just from this one sentence.
And, more seriously, there isn't really such a thing as a common-sense proposal with SQL. The grammar is so warped after all these years that there isn't a path to consistency and the broken attempt at English syntax has rendered it nearly incomprehensible for both human and machine parsing. Any change to anything could have bizarre flow on effects.
I'd love to see trailing commas added to SELECT though. Given the mess it isn't possible to make the situation worse and the end of the list being special can be infuriating.
Also, to generalize a bit: if a human is expected to read it, the way humans write should be able to be parsed by it. That's subjective, to a point, but it's an easy rule-of-thumb to remember. Trailing commas are so common that people have built workarounds for them. Therefore, they can be understood as "the way humans write". If you're writing a language that you still want to be readable by humans, you really should account for that. And, no shade for it not already being done. I'm just reiterating that there should be NO pushback to allowing trailing commas. It's a completely "common-sense" proposal.