Thread: append columns that are null

I have function that appends 2 columns, like
"new.field1 = new.field2||new.field3",
but when field 3 is null, then the entire outcome is null, while I 
expected just field2, since when I append nothing to field2, I get 
field2, right?
Is this standard behaviour, and if so, is there another append function 
that I can use that doesn't behave like this?

nobody wrote:
> "Gerwin Philippo" <gerwin@vernet.nl> wrote in message
> news:40ec1043$0$559$e4fe514c@news.xs4all.nl...
> 
>>I have function that appends 2 columns, like
>>"new.field1 = new.field2||new.field3",
>>but when field 3 is null, then the entire outcome is null, while I
>>expected just field2, since when I append nothing to field2, I get
>>field2, right?
>>Is this standard behaviour, and if so, is there another append function
>>that I can use that doesn't behave like this?

3 + unknown value = unknown value

its also unknown if 3 is bigger, smaller or equal to an unknown value.

-- 
Hans de Bruin

http://eratosthenes.xs4all.nl

"Gerwin Philippo" <gerwin@vernet.nl> wrote in message
news:40ec1043$0$559$e4fe514c@news.xs4all.nl...
> I have function that appends 2 columns, like
> "new.field1 = new.field2||new.field3",
> but when field 3 is null, then the entire outcome is null, while I
> expected just field2, since when I append nothing to field2, I get
> field2, right?
> Is this standard behaviour, and if so, is there another append function
> that I can use that doesn't behave like this?

COALESCE is your friend...