[QGIS-Developer] Filtering features in a layer by a report group

[Nyall Dawson]

On Thu, 8 Aug 2019 at 09:50, Tim Sutton <tim at kartoza.com> wrote:

> We don’t have anything equivalent of the layout atlas’s filter features right? Would be nice to be able to filter report group records by some criteria.

Unfortunately not yet. I was hoping someone would step up and sponsor
this, but it's also been on my wip document planning future
improvements to layouts/reports which could be done in a co-funding
manner...

Nyall

>
> Yup I am aware of the provider part but shouldn’t one still be able to interpolate QGIS expressions (or at least variables) into the filter expression? I am thinking the equivalent here of doing
>
> Select * from layer_foo where name=“@some_name”
>
>
> That would work in some cases, but variables can also be QGIS specific
> values like geometry objects. So then every provider would need logic
> to convert these to something which works for that backend. I suspect
> this is a dangerous path to go down, since we'd constantly be trying
> to close corner cases where a particular filter isn't working
> correctly for a particular backend.
>
> I think I'd prefer a mode where you could choose from either filtering
> using the backend syntax OR qgis expressions. Given that we now have
> good support for "compiling" QGIS expressions back to the closest
> possible provider native equivalent, and that all providers handle
> this, in most cases there should be very minimal loss of performance.
> And the benefit would be that ALL QGIS expressions would be guaranteed
> to work correctly regardless of the provider backend…
>
>
> Thanks for the feedback above - I will go with the cheating approach of using rule based renderers for filtering data for now.  But nice to know you have a plan in mind for some crowdfunding or grant work in the future :-P
>
> Regards
>
> Tim
>
>
>
> Nyall
>
>
>
>
> Which gets replaced with the actual name each time a read request  is made.
>
>
> Thanks!
>
> Regards
>
> Tim
>
>
>
> See https://github.com/qgis/QGIS/issues/24932
>
> Nyall
>
>
>
>
> Thanks!
>
> Regards
>
> Tim
> —
>
>
>
>
>
>
>
>
> Tim Sutton
>
> Co-founder: Kartoza
> Ex Project chair: QGIS.org
>
> Visit http://kartoza.com to find out about open source:
>
> Desktop GIS programming services
> Geospatial web development
> GIS Training
> Consulting Services
>
> Skype: timlinux
> IRC: timlinux on #qgis at freenode.net
>
> I'd love to connect. Here's my calendar link to make finding time easy.
>
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>
> —
>
>
>
>
>
>
>
>
> Tim Sutton
>
> Co-founder: Kartoza
> Ex Project chair: QGIS.org
>
> Visit http://kartoza.com to find out about open source:
>
> Desktop GIS programming services
> Geospatial web development
> GIS Training
> Consulting Services
>
> Skype: timlinux
> IRC: timlinux on #qgis at freenode.net
>
> I'd love to connect. Here's my calendar link to make finding time easy.
>
>
> —
>
>
>
>
>
>
>
>
> Tim Sutton
>
> Co-founder: Kartoza
> Ex Project chair: QGIS.org
>
> Visit http://kartoza.com to find out about open source:
>
> Desktop GIS programming services
> Geospatial web development
> GIS Training
> Consulting Services
>
> Skype: timlinux
> IRC: timlinux on #qgis at freenode.net
>
> I'd love to connect. Here's my calendar link to make finding time easy.
>