Not sure if "never", but from the new Spanner paper[1]: > While we have seen comparatively little demand for this feature internally, supporting such semantics

Not sure if "never", but from the new Spanner paper[1]: > While we have seen comparatively little demand for this feature internally, supporting such semantics improves compatibility with other SQL systems and their ecosystems and is on our long-term radar. [1] http://dl.acm.org/authorize?N37621 http://dl.acm.org/authorize?N37621