On Wed, Dec 20, 2017 at 5:17 PM, Peter Eisentraut < peter.eisentr...@2ndquadrant.com> wrote:
> On 12/20/17 10:29, Tom Lane wrote: > > Please say that's just an Oracle-ism and not SQL standard, because it's > > formally ambiguous. This is required to work by spec: > > > > regression=# select x as of from (values(1)) t(x); > > of > > ---- > > 1 > > (1 row) > > > > so it's not possible for us ever to support an expression that includes > > top-level "AS OF" (or, pretty much, "AS anything") without some rather > > enormous pushups. > > The SQL standard syntax appears to be something like > > "tablename" [ AS OF SYSTEM TIME 'something' ] [ [ AS ] "alias" ] > > That's not going to be fun to parse. > There was a presentation about this given at FOSDEM PGDay a couple of years back. Slides at https://wiki.postgresql.org/images/6/64/Fosdem20150130PostgresqlTemporal.pdf . -- Magnus Hagander Me: https://www.hagander.net/ <http://www.hagander.net/> Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>
