"milimeter@163.com" <milimeter@163.com> writes:
> I found that in postgresql, we can only use "select login_name as name from
> users;" to get an alias "name" for column "login_name", but in most other
> databases we can omit the "as", that is "select login_name name from users;".
AS is not optional in Postgres, and will never be so unless we choose to
drop support for postfix operators, which I consider an unlikely choice.
Example: in
SELECT foo ! bar;
is the "!" an infix operator, or is it postfix with the intended meaning
SELECT (foo!) AS bar;
regards, tom lane