Hi,

So how is concat(NULL,fieldname) any better than COALESCE(fieldname,''). To me it is the same complexity and not really an improvement. But maybe I don't get it. The only slight advantage would be that "concat" may be a more familiar term than coalesce. But if you come from a database background you already know COALESCE. Any serious GIS professional needs to know databases.

Another small thing:
Do not mix up double quotes (") and single quotes ('). Whenever you use a string, do use single quotes, when you use an attribute either use no quotes or double quotes for some providers if you use capital letters in field names (which is discourage anyway).

Andreas

On 20.09.2015 12:59, Matthias Kuhn wrote:
Hi Phil,

In addition to COALESCE I'd like to promote the use of the function *CONCAT()* which treats NULL values as empty strings (it was changed recently, it's probably since 2.10) what makes it very handy.

Example:

NULL || "hello" -> NULL

vs.

CONCAT( NULL , "hello") -> "hello

vs.

COALESCE( NULL, "" ) || "hello" -> "hello"

Cheers,
Matthias

On 09/20/2015 09:54 AM, Phil (The Geek) Wyatt wrote:

Hi Folks,

I am working with LIST Address Points data from http://listdata.thelist.tas.gov.au/opendata/ (Specifically Clarence Municipality) and I need to concatenate into one field the full address of each location. I am struggling to figure out how to do it when there are fields for unit numbers, building names, numbers to and from etc. Many of the fields are also NULL so clearly I want those fields disregarded.

Can someone give me a quick heads up on how to NOT add the data from a field that has NULL?

Chances are I will be doing this regularly so I am keen to document the required expressions for others to use as well.

Cheers - Phil

Volunteer Mapper - Red Cross <http://www.redcross.org.au/volunteering.aspx>



_______________________________________________
Qgis-user mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/qgis-user



_______________________________________________
Qgis-user mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/qgis-user

_______________________________________________
Qgis-user mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/qgis-user

Reply via email to