Re: [SQL] isnull function]

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: kachun(at)pathlink(dot)com (Kachun Lee)
Cc: hackers(at)postgreSQL(dot)org (PostgreSQL-development)
Subject: Re: [SQL] isnull function]
Date: 1998-06-27 02:11:56
Message-ID: 199806270211.WAA17393@candle.pha.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers pgsql-sql

>
> 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(at)candle(dot)pha(dot)pa(dot)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)

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Bruce Momjian 1998-06-27 05:14:38 Re: [HACKERS] Problem after removal of exec(), help
Previous Message Brett McCormick 1998-06-27 01:35:44 operator error

Browse pgsql-sql by date

  From Date Subject
Next Message James Olin Oden 1998-06-27 10:29:30 Re: [SQL] isnull function]
Previous Message Kachun Lee 1998-06-26 23:45:54 Re: [SQL] Date fields and libpq....