I'm certainly eager to see official SQLite support as well. In the mean time, the overlap between postgres and SQLite syntax is enough that a lot of my "postgres" definitions in sqlc work just fine in SQLite. The recent addition of "RETURNING" (https://www.sqlite.org/lang_returning.html) to SQLite was a big help since that was a standard part of sql used for postgres with sqlc if you wanted the last insert ID.
