You should worry about whether your chosen DBMS will support the necessary
features for your application.
You should not worry about whether it meets a checklist requirement of
SQL99, to my knowledge no database, commercial or otherwise, does.
As it happens, Postgre supports a wider portion of the standard than most.
But it's important to realize that nearly all the DMBS's out there support
the same feature and enable the same programming techniques as are stated in
SQL99, just with differing syntax.
In terms of the standard itself, there are vast portions of the extended
standard that vendors have declaired they do not intend to impliment.
A better way to ask this question is: of the features I plan to use for my
application, which databases expose those features with SQL99 syntax? This
is what governs your application being portable.
The SQL99 standard is online. If I recall, it's about 2,000 pages.
> PortgreSQL is implementing full SQL99 specification? In which relase?
>
> Where can i find further info about ANSI SQL 99 and others DBMS which
> implement SQL 99?
>
> Thanks in advance!