[Qgis-user] Filtering NULL values from WFS

[pathmapper]

Hi,

you could try a filter with

  "end_date" is NULL

or

  "end_date" is not NULL

And it should be possible to combine filters, e.g. with AND:

"end_date" != '2005-12-31' AND "end_date" is NULL

Cheers,
Björn

On 26.08.2025 16:46, Reetz, Michael (NLPVW) via QGIS-User wrote:
> Hello group,
> 
> I've added a WFS-layer to a project try to define filters on different
> attributes. It seems not to be possible to filter for NULL values.
> 
> Example:
> 
>  	* 1932 records in total
> 	* 376 records with a value in a date attribute
> 	* 20 records with 2005-12-31 as value
> 
> If I set the filter to "end_date" = '2005-12-31' the result is 20
> records.
> 
> If I set the filter to "end_date" != '2005-12-31' the result is 356
> records. So only records that have an end date are recognized. Record
> with NULL as end date are ignored.
> 
> Filtering in the attribute table with "is_empty_or_null" works but
> only for selection.
> 
> Is this "normal" behaviour with WFS layers or is there a way to define
> a filter string that work for all records?
> 
> QGIS-Version is 3.40.4-Bratislava
> 
> Best regards
> 
> Michael
> 
> *****************************************
> 
> Michael Reetz
> 
> Datenbanken und Anwendungsentwicklung
>  Nationalpark-Verwaltung Niedersächsisches Wattenmeer
>  Virchowstr. 1 | 26382 Wilhelmshaven
>  Tel.: +49 (0) 4421 911 291
>  e-mail: michael.reetz at nlpvw.niedersachsen.de
>  Web: https://www. [1]nationalpark-wattenmeer.de
> 
> 
> 
> Links:
> ------
> [1] https://www./
> 
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