Re: string is sometimes null ?

Поиск
Список
Период
Сортировка
От Stephan Szabo
Тема Re: string is sometimes null ?
Дата
Msg-id 20040930073249.Q8163@megazone.bigpanda.com
обсуждение исходный текст
Ответ на Re: string is sometimes null ?  (Graeme Hinchliffe <graeme.hinchliffe@zeninternet.co.uk>)
Список pgsql-general
On Thu, 30 Sep 2004, Graeme Hinchliffe wrote:

> > If monthcurr or username are null, the above will be null.
> > Anything || NULL => NULL.
>
> AH! thanks sorted it now.  That is not the behaviour I would have
> expected :)
>
> Is there a concatination operator that will not do this? IE
>
> if
>
> var1 || var2 || var3
>
> and var2 is null would result in just var1var3  ?

You can use coalesce as suggested... However, since you are building a
statement, think about what you want to do when either of those are NULL.
You might want to use an empty string, or perhaps instead of ='' you might
actually be wanting an IS NULL clause, etc...

В списке pgsql-general по дате отправления:

Предыдущее
От: peter pilsl
Дата:
Сообщение: problems with lower() and unicode-databases
Следующее
От: Tom Lane
Дата:
Сообщение: Re: 7.3.4 vacuum/analyze error