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## Re: isnull

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Julie Hunt wrote: > Yes, you're right. I remember attempting to do an outer left join using the > nullif but without success so I used the case function instead with success. > Maybe someone else knows more about nullif and why it doesn't seem to work. > > Regards, > Julie > I've actually taken a closer look at the web page and not only did the name change, but I now notice that they change what it is supposed to do as well. It does work as currently defined, but I needed something that does what the original documentation said: IFNULL(input,non-NULL substitute) return second argument if first is NULL Example: IFNULL(c1, 'N/A') > > Joseph Shraibman wrote: > > > Julie Hunt wrote: > > > > > Sorry, I haven't come across ifnull > > > > Ah, I think the documentation that came with 6.5.3 was wrong, because > > http://www.postgresql.org/docs/postgres/functions.htm#AEN2257 has the function > > nullif where ifnull was in my documentation. I don't get errors now, but it > > just doesn't seem to do it's job. > > > > playpen=> insert into tablea values (100, null); > > INSERT 23168 1 > > playpen=> select * from tablea; > > indexa|data > > ------+---- > > 1| 1 > > 2| 2 > > 3| 2 > > 4| 4 > > 7| 7 > > 6| 8 > > 5| 8 > > 100| > > (8 rows) > > > > playpen=> select *, data from tablea; > > indexa|data|data > > ------+----+---- > > 1| 1| 1 > > 2| 2| 2 > > 3| 2| 2 > > 4| 4| 4 > > 7| 7| 7 > > 6| 8| 8 > > 5| 8| 8 > > 100| | > > (8 rows) > > > > playpen=> select *, nullif(data, 9) from tablea; > > indexa|data|case > > ------+----+---- > > 1| 1| 1 > > 2| 2| 2 > > 3| 2| 2 > > 4| 4| 4 > > 7| 7| 7 > > 6| 8| 8 > > 5| 8| 8 > > 100| | > > (8 rows) > > > > > > > > Julie > > > > > > >Oops, my mistake. I meant ifnull. Whenever I try to use ifnull I get an > > > >error so I have to use a case when a = null then default else a end. > > > > > > > >Julie Hunt wrote: > > > > > > > >> There is a space between is and null: is null > > > >> > > > >> Regards > > > >> > > > >> Joseph Shraibman wrote: > > > >> > > > >> > Could someone give me an example of isnull? Whenever I try it I get an > > > >> > error message. > > > >

- Re: isnull at 2000-03-30 22:58:32 from Julie Hunt

- Re: isnull at 2000-03-31 01:10:42 from Julie Hunt
- Re: isnull at 2000-03-31 01:43:00 from Bruce Momjian

Next: From:Tom LaneDate:2000-03-31 00:11:49Subject: Re: isnullPrevious: From: Julie HuntDate: 2000-03-30 23:06:56Subject: Re: removing a field from a table