| From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
|---|---|
| To: | Ingmar Brouns <swingi(at)gmail(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: concat(NULL,NULL) returns empty string |
| Date: | 2011-12-08 16:03:43 |
| Message-ID: | CAFj8pRDChmYuX_a5LaYFWufUTt5gQbfNcA5hDQfHfyYA5u4P=w@mail.gmail.com |
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| Lists: | pgsql-general |
Hello
2011/12/8 Ingmar Brouns <swingi(at)gmail(dot)com>:
>
> Hi,
>
> The documentation of the function concat states: Concatenate all arguments.
> NULL arguments are ignored.
> Intuitively I would expect that
>
> concat(NULL, NULL) IS NULL
>
> but this is not the case as it equals the empty string. As no empty string
> was passed, the empty string seems
> to come from nowhere. I found this behavior not immediately clear from the
> documentation..
>
yes - it returns empty string - concat is "barier" to nulls
it should be better documented
Regards
Pavel Stehule
> Kind regards,
>
> Ingmar Brouns
>
>
>
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