Subject Re: [firebird-support] Re: Making evaluation of UDFs constant across a query
Author Ann Harrison

>  After reading the FB v2.1 release
> notes I thought I understood that
>   timestamp 'now'
> was the equivalent of
>   cast('now' as timestamp)
> but after using it in a few places I found it is definitely not
> the same.  Nor is it quite the same as current_timestamp.
> (I am currently assuming that "timestamp 'xxx'" is truly the
> equivalent of cast('xxx' as timestamp) is most other cases.)

The string value 'now' when assigned to a date time type gives
you the current time and date. That, 'today', 'tomorrow'', and
'yesterday' were the original time and date sources in gds/galaxy,
way before SQL had any sense of time. CURRENT_TIMESTAMP
(like all the CURRENT_xxx special variables) give you the time
and date at the start of the current statement.

So yes, they are different, it is by design, and the SQL Standard
cares a great deal more about cursor stability than the designer
of InterBase.