Re: LOOping clobbering variable

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От Michael Fuhr
Тема Re: LOOping clobbering variable
Дата
Msg-id 20050102050700.GA13653@winnie.fuhr.org
обсуждение исходный текст
Ответ на LOOping clobbering variable  ("K Anderson" <msmouse@kittymail.com>)
Список pgsql-novice
On Sat, Jan 01, 2005 at 07:38:16PM -0800, K Anderson wrote:

> The enclosed function returns a proper result only when the LOOP
> and its enclosed functionality is removed from the function. Notice
> near the return I have  xml=xml||'</transaction>';
>
> That should at the least return what ever is in xml with
> </transaction> concatinated, or so I would hope. But it's empty.

I'd guess that one of the values you're concatenating is NULL.
Concatenating NULL with anything results in NULL, so if you assign
that back to xml then all subsequent concatenations will also result
in NULL.

You can use COALESCE to convert NULLs to empty strings.

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/

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