Hi,
the PG documentation is slightly inconsistent. This site here:
http://www.postgresql.org/about/history/
states that SQL was implemented in 1995, and this site here states:
http://www.postgresql.org/docs/9.4/static/history.html
that it was implemented in 1994.
After talking with Andrew Yu about this, he remembers that the work on
implementing SQL started in 1994, and was finished in 1995.
-- Andreas 'ads' Scherbaum
German PostgreSQL User Group
European PostgreSQL User Group - Board of Directors
Volunteer Regional Contact, Germany - PostgreSQL Project