isnull function

Is there an isnull function avaliable in postgres, such as:

select isnull(dt_field, 'now') ...

Thanks

I don't tbink so, but it would be nice. I think Ingres has it. It also
would not be hard to write as a loadable function.

-- 
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

At 03:13 PM 6/26/98 -0400, you wrote:

Is there an isnull function avaliable in postgres, such as:

select isnull(dt_field, 'now') ...

Thanks

I don't tbink so, but it would be nice. I think Ingres has it. It also
would not be hard to write as a loadable function.

-- 
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
+  If your life is a hard drive,     |  (610) 353-9879(w)
+  Christ can be your backup.        |  (610) 853-3000(h)

I tried, but the following code does not seem to work:

#include <string.h>
#include <stdio.h>
#include "postgres.h"
#include "libpq-fe.h"
#include "utils/dt.h"

DateTime * is_null(DateTime *, DateTime *);

DateTime * is_null (DateTime * dt, DateTime * def)
{
return dt ? dt : def;
}

I searched the doc/maillist, and I could not find how to test an arg for
NULL value. Should I post this to HACKER?

I posted this question a while back and received a response of 'is null'
such as:

select * from try where field is null;

Will give you all entries where the field 'field' does not yet contain a
value. Works great and I hope will answer your original question.
(Now if only I could find an easy answer for mine :)

--
Colin Dick
On Call Internet Services
cdick@mail.ocis.net

On Fri, 26 Jun 1998, Kachun Lee wrote:

I tried, but the following code does not seem to work:

#include <string.h>
#include <stdio.h>
#include "postgres.h"
#include "libpq-fe.h"
#include "utils/dt.h"

DateTime * is_null(DateTime *, DateTime *);

DateTime * is_null (DateTime * dt, DateTime * def)
{
return dt ? dt : def;
}

I searched the doc/maillist, and I could not find how to test an arg for
NULL value. Should I post this to HACKER?

Having DateTime* be a NULL does not represent a NULL value in SQL
internally.

Not sure how to do it, because I don't rememeber where the NULL checking
is done.

-- 
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)

Is there an isnull function avaliable in postgres, such as:

select isnull(dt_field, 'now') ...

Thanks

I don't tbink so, but it would be nice. I think Ingres has it. It also
would not be hard to write as a loadable function.

Is it possible to do something like:

select * from blah where x = ''

and get what he is asking for?

...james