2008/9/11 Tobias Anstett <tobias.anstett@xxxxxxxxxxxxxxxxxxxxx>:
> Hi,
>
>
>
> in my special case I'd like to check if a XML[] is empty, because postgres
> doesn't implement any equality operators, this is not a 'simple' task.
>
>
>
> My current solution is:
>
>
>
> SELECT * FROM sometable WHERE XMLSERIALIZE(CONTENT ((XPATH('/a:bar,
> somexmlcolumn, ARRAY[ARRAY['a', 'http://foo]]))[1]) AS text)<>''
>
>
>
> But there must be a better way – maybe I missed something important - I also
> tried queries like the following:
>
>
>
> SELECT * FROM sometable WHERE (XPATH('/a:bar', somexmlcolumn,
> ARRAY[ARRAY['a', 'http://foo']]))<>('{}'::XML[])
>
>
>
> Any ideas and feedback are welcome.
>
>
>
> Cheers, Tobias
What about array_upper():
select array_upper('{}'::XML[], 1)
NULL will be returned if the array is empty in 1-dim.
--
Hitoshi Harada
