[Qgis-user] Concatenate address fields with NULLS

[Andreas Neumann]

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>
>>
>>
>>
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>
>
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