[postgis-devel] [PostGIS] NULL-values ar function arguments

[Nicklas Avén]

We have a wiki-page and discussion about EMPTY GEOMETRIES

should we have something corresponding about handling of NULL-values?

I just opened #1078 about NULL-values as second argument in
ST_Difference

In ST_Collect we return the not null values 

Other functions I have checked returns NULL if a null-value is involved.

I think this is specially interesting incases when you use left or right
join like in the gis.stackexchange question that lead to my ticket:
http://gis.stackexchange.com/questions/11592/difference-between-two-layers-in-postgis


In the ticket Paul gives the example of btrim('this', NULL) which also
returns NULL instead of 'this' as I would expect.

What is the arguments for this behavior?


Regards

Nicklas