Re: Specifying text to substitute for NULLs in selects

On Thu, 6 Nov 2008 17:44:42 -0800 (PST)
pcreso(at)pcreso(dot)com wrote:

>
> 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 select output,
> 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 setting a system
> variable to specify this?

wtw_drupal=# create schema test;
CREATE SCHEMA
wtw_drupal=# create table test.test(c1 text);
CREATE TABLE
wtw_drupal=# insert into test.test values(null);
INSERT 0 1
wtw_drupal=# insert into test.test values('test');
INSERT 0 1
wtw_drupal=# \copy test.test to stdout null as 'BANANA'
BANANA
test
wtw_drupal=# drop schema test cascade;
NOTICE: drop cascades to table test.test
DROP SCHEMA

everything clearly explained in the COPY manual:
http://www.postgresql.org/docs/8.1/static/sql-copy.html

--
Ivan Sergio Borgonovo
http://www.webthatworks.it