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.
Well, the SQL committe seem to specialise in parser torture.
