My team is only writing tree-sitter parsers as part of working on GitHub developer productivity features like Code Navigation. So the short version is that we (i.e., my team at GitHub) haven't written a tree-sitter parser for SQL because we haven't targeted SQL for Code Nav support yet.

That said, this is exactly why we've released tree-sitter as an open-source project. That way there's no need for anyone to be blocked on my team finding the time to work on an SQL parser. Most extant tree-sitter parsers [1] have been developed by external language communities, and not by the core tree-sitter maintainers.

(Also note that SQL is a particularly wrinkly language, since there are so many different dialects. Are you looking for an ANSI SQL parser? A MySQL SQL parser? One that covers all of them to some degree?)

[1] https://tree-sitter.github.io/tree-sitter/#available-parsers