So reading responses from all, here is a SQL test I did on few RDBMS:
select 'John'
'Doe' as rrr
from information_schema.tables
limit 1;
PG output
rrr
---
JohnDoe
Oracle and mysql gave same output as PG with no error
SQLServer: Syntax error near 'as'.
DB2 gave same error as SQLServer.
