What's the version of pgsql?
postgres=# show server_version;
server_version
----------------
8.1.0
(1 row)
postgres=# CREATE OR REPLACE FUNCTION foo (v_s1 varchar, v_s2 varchar)
postgres-# RETURNS varchar AS $$
postgres$# BEGIN
postgres$# RETURN v_s1 || '\\' || v_s2;
postgres$# END;
postgres$# $$ LANGUAGE plpgsql;
CREATE FUNCTION
postgres=# SELECT foo ('pgsql', 'hackers');
foo
---------------
pgsql\hackers
(1 row)
Regards,
William ZHANG