[Qgis-user] Concatenate address fields with NULLS

[DelazJ]

Hi Andreas,

2015-09-21 8:39 GMT+02:00 Andreas Neumann <a.neumann at carto.net>:

> 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.
>
> Concatenate labels is a frequent question in GIS forums. Maybe we are not
all _serious_ GIS professional but even QGIS _simple_ users should be able
to easily concatenate labels without being puzzled by NULL values handling
imho.


> 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>
>
>
>
>
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