The following bug has been logged online:
Bug reference: 6181
Logged by: Itagaki Takahiro
Email address: itagaki(dot)takahiro(at)gmail(dot)com
PostgreSQL version: 9.1 RC1 (x86)
Operating system: Windows 7 (64bit)
Description: concat_ws() incompatibility with MySQL
Details:
For query concat_ws('/', NULL, 'X'),
PostgreSQL 9.1 returns '/X', but MySQL returns 'X'.
I think postgres should return 'X' because of compatibility.
Another reason is that both of the two queries below return 'X'.
- concat_ws('/', 'X', NULL)
- array_to_string(ARRAY[NULL, 'X'], '/')