Thread: isnull function
Is there an isnull function avaliable in postgres, such as: select isnull(dt_field, 'now') ... Thanks
> > 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: > 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? >
> > 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