The following bug has been logged online:
Bug reference: 5257
Logged by: Roman Kononov
Email address: kononov(at)ftml(dot)net
PostgreSQL version: 8.4.2
Operating system: GNU/Linux x86_64
Description: wrong results of SUBSTRING with SQL regular expressions
Details:
test=# select substring('34' from '(2|3)#"4#"' for '#');
substring
-----------
3
(1 row)
test=# select substring('^' from '#"^#"' for '#');
substring
-----------
(1 row)
test=# select substring('$' from '#"$#"' for '#');
substring
-----------
(1 row)
These look wrong according to the PG documentation.