Обсуждение: timestamp/now in views

Sorry for being an idiot but I saw something similar to this in the docs but
haven't been able to find it since.
I tried creating a view using the following syntax
CREATE VIEW prev_day AS SELECT * FROM audit WHERE audit_datetime >
(current_timestamp - interval'24 hours');

Now as some of you will pick up, this creates a view with the current
timestamp set to the creation time of the view, not the actual time the view
was executed.
I hacked around with various combos of quote marks and tried now() and so
on, but to no avail.

Can someone enlighten me?

Cheers,Graeme

"Graeme Merrall" <gmerrall@email.com> writes:
> I tried creating a view using the following syntax
> CREATE VIEW prev_day AS SELECT * FROM audit WHERE audit_datetime >
> (current_timestamp - interval'24 hours');

> Now as some of you will pick up, this creates a view with the current
> timestamp set to the creation time of the view, not the actual time the view
> was executed.

Yes --- this is fixed in current sources, but that doesn't help you on
release versions :-(

> I hacked around with various combos of quote marks and tried now() and so
> on, but to no avail.

Just substituting now() for current_timestamp seemed to work fine for
me in 6.5.3:

play=> CREATE VIEW prev_day AS SELECT * FROM audit WHERE audit_datetime >
play-> (now() - interval'24 hours');                                     
CREATE
play=> \d prev_day                                                       
View    = prev_day
Query   = SELECT "audit"."f1", "audit"."audit_datetime" FROM "audit" WHERE ("datetime"("audit"."audit_datetime") >
("datetime"("now"())- '@ 1 day'::"timespan"));
 

As you can see, the stored form of the query still has now() rather than
a constant datetime value...
        regards, tom lane

>
> Sorry for being an idiot but I saw something similar to this in the docs but
> haven't been able to find it since.
> I tried creating a view using the following syntax
> CREATE VIEW prev_day AS SELECT * FROM audit WHERE audit_datetime >
> (current_timestamp - interval'24 hours');

    ... WHERE audit_datetime >
                timestamp('now'::text) + '@24hours'::interval

    That one should work.


Jan

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