Sue Humphrey <sue_humphrey@yahoo.com> writes:
> I would like examples of functions using update, insert and
> delete, where LANGUAGE 'SQL', both how to write them and how to
> use them.
Have you read the documentation?
http://www.ca.postgresql.org/users-lounge/docs/7.2/postgres/xfunc-sql.html
The first couple of examples seem to cover the territory ...
regards, tom lane