Обсуждение: Defining string to represent null values in select

Поиск
Список
Период
Сортировка

Defining string to represent null values in select

От
Brent Wood
Дата:
Hi,

I can specify the text used to represent a null value in output from copy, but I'd like to do something similar is
selectoutput, eg: all NULL values are represented by NA or NaN. 

I can't find anything in the docs about this.

This could be managed using case statements around all the columns in the query, but is there a simpler way, like
settinga system variable to specify this? 

Thanks,

  Brent Wood

Re: Defining string to represent null values in select

От
Andreas Kretschmer
Дата:
Brent Wood <pcreso@yahoo.com> schrieb:

>
> Hi,
>
> I can specify the text used to represent a null value in output from copy, but I'd like to do something similar is
selectoutput, eg: all NULL values are represented by NA or NaN. 

COALESCE:
test=*# select coalesce(NULL, 'NaN');
 coalesce
----------
 NaN



Andreas
--
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect.                              (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly."   (unknown)
Kaufbach, Saxony, Germany, Europe.              N 51.05082°, E 13.56889°