[QGIS-Developer] QGIS expression based layer filters

[Raymond Nijssen]

Hi David,

That sounds very useful to me! I often find myself struggling writing 
the right expression, or even adding a column to my data to be able to 
set the desired provider filter.

But I think the provider filter is more efficient as it really prevents 
the data from the file ending up in QGIS. Or am I wrong? Is there a 
penalty for filtering data in QGIS?

BTW, even with a performance penalty this functionality could be super 
handy for small datasets!

Kind regards,
Raymond


On 9/24/25 14:56, David Signer via QGIS-Developer wrote:
> Hi there
> 
> I've been considering enhancing the Query Builder (accessible via Layer 
> -> Filter...) by QGIS expression based filters. At least with project 
> and global scope.
> Maybe with tabs to distinguish between "provider side filter" (current 
> functionality) and "expression filter" (new functionality).
> 
> Any opinions on this? In my view, this could be valuable because it's 
> available on all kinds of data-layers and allows us to use variables and 
> functions for filtering as well.
> 
> Thanks for any feedback and cheers
> Dave
> 
> --
> 
> Dave Signer
> Senior Developer & INTERLIS Architect
> OPENGIS.ch - Team QGIS & Industry Solutions
> 
> 
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