Wow, TIL. Great tip for those random one-off queries you have to bash out when investigating a problem.

Please never let this vile shortcut work its way into your production code.

I've seen quite a few production queries that use indexes in GROUP BY and ORDER BY; it's quite common. Probably partially because linters/code review/etc are lightweight to nonexistent amongst the analysts/data science types that I tend to work with.

Indexes are used all over for grouping an ordering, I was objecting only to the syntax of ORDER BY <number>