How to check if an array is empty

["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