Am 20.09.2015, 09:54 Uhr, schrieb Phil (The Geek) Wyatt
<[email protected]>:
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
Hi,
having NULL values in attributes is not easy to handle for those who have
no idea what terms to search for on the internet.
There is the coalesce function in field calculator:
coalesce("Fieldname1",'') will return your attribute, in case its NULL it
will return en empty string (or what ever you like).
Concatenating coalesce("Fieldname1",'') || coalesce("Fieldname2",'') ...
But this will just paste together all attributes, so add || ' ' to the
field name to get spaces between the attributes.
coalesce("Fieldname1" || ' ','') || coalesce("Fieldname2" || ' ','') ...
(it seems that this handles NULL & something = NULL)
For a lot of fields, this is a boring work to put it into the expression
editor , so I normally paste the attribute table (click the up-left margin
cell to mark everything, then hit ctrl-c) into a spreadsheed. Delete all
data except the header line, clip and insert this line transposed, so it
starts in cell A1 downwards.
in cell B1 start ="coalesce(" & A1 & " ||'','') ||
and drag this down.
You can than just copy the range it paste it into the expression editor in
QGIS. Remove the last ||
Hope this helps.
Bernd
--
Bernd Vogelgesang
Siedlerstraße 2
91083 Baiersdorf/Igelsdorf
Tel: 09133-825374
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