Apply the same filter expression at the provider level to several layers of the TOC in QGIS in one single operation

Question

I have a QGIS project with plenty of geometric layers coming from a PostGIS database.

Each and every layer has the same filter expression to limit the display to a same object: the filter simply being "id=<whatever_id_i_need_to_display>".

This allows me to limit the display to only the desired feature. Indeed, there are more than 200'000 features in the DB, displaying them all tends to slow down, if not crashing QGIS.

But it's somewhat tedious to manually change the filter on dozens of layers.

Is it possible to set such filter expression to many layers in one operation using the GUI?

I "naturally" tried to right click on the selection of all the layers I'd like to change the filter, but when the query builder window opens, it specifically targets the one layer I mouse-clicked on it, not taking into account all the selected layers.

There seems to be a Python solution: How to apply a filter to multiple vector layers in QGIS? but unfortunately there is a bug with SIP on my installation, so all Python related stuff is not available. Therefore, I am looking for a simple operation that I can perform with the graphical interface.

Info:

QGIS version	3.24.2-Tisler
QGIS code revision	13c1a02865
Qt version	5.15.3
Python version	3.10.4
GDAL/OGR version	3.4.1
PROJ version	8.2.1
EPSG Registry database version	v10.041 (2021-12-03)
GEOS version	3.10.2-CAPI-1.16.0
SQLite version	3.37.2
PDAL version	2.3.0
PostgreSQL client version	unknown
SpatiaLite version	5.0.1
QWT version	6.1.4
QScintilla2 version	2.11.6
OS version	Ubuntu 22.04 LTS

EDIT:

Babel's answers are valid and his first one is really nice when working with few simple features.
But in my situation, I do have some layers with large data (up to hundreds of MB), therefore, when I remove the filter expression on those layers and rely only on the style definition, QGIS loads each and every features even so it has been told to display only one. And by loading them all, it consumes all the memory, up to the crash.
Therefore, I absolutely need to build a filter expression at the provider level, namely my PostgreSQL database, to only retrieve one single (or a small subset of) features for visualization purposes, and of course being able to switch from feature N to M in less than 2 seconds, for all my 100 layers.
The key idea is really to be able to switch the visualization to any other feature based on its id, for all layers in one quick and single operation.

EDIT 2:

The advanced filter expression within the attribute table is not working. Indeed, it permits the filtering of feature, but only once everything has been loaded inside QGIS. Therefore, if I apply a filter based on @id_def as suggested, it will still show 200'000 features when I show the feature count in the table of content, and when enabling a single layer having large data, it again eats all my memory up to the crash:

So, it's mandatory that this filter is being applied as the provider level, i.e. before querying the features. Well actually not really before but for the querying of the feature(s).

Answer 1

If you don't use the Provider Feaure Filter to hide some features, but use Layer Styling > Enable Symbol layer to hide some of the features, you can use a custom variable with QGIS expressions to create conditions what should be hidden.

1. Define a custom variable Menu Project > Properties > Variables. In my case, I name it id_def and assign a value of 21.

2. In Layer Styling, use data driven override of Enable Symbol layer and set an expression. In my case, I use id < @id_def to show only features with id < 21.

3. You can copy/paste style between layers to avoid repeating this separately for each layer. If you now change the variable's value to 5, all layers will just show features with id < 5.

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Edit

You could also try to define the filter using the variable at the bottom of the attribute table with Advanced Filter (Expression).

Answer 2

Another option would be to filter the objects in the PostGIS database, creating a view before loading to QGIS and that load this view to work with in QGIS.

Something like the following to generate a view of all features with id >= 5 or id >= 10:

create view myview as select * from mytable as t
where t.id <= 5 or t.id >= 10

Answer 3

Too late answer, I think, but may be useful for others:

I had the same problem, needing to use the same filter expression on a number of layers, '"versjon"=<some version number>' So I did a quick and dirty python script:

def filterlayers(versjon):
    for layername in ('sitedata','kabelsjekk','kabeldata'):
        print(layername)
        layer = QgsProject.instance().mapLayersByName(layername)[0]
        layer.setSubsetString(f'"versjon" = {versjon}')

Running this script once in the python terminal after starting QGIS, I can later on run

filterlayer(13)

to get the three layers filtered on "versjon"=13.

If you want to be more flexible on the content of the filter, you can send in the entire filterstring instead:

def filterlayers(filter):
    for layername in ('sitedata','kabelsjekk','kabeldata'):
        print(layername)
        layer = QgsProject.instance().mapLayersByName(layername)[0]
        layer.setSubsetString(filter)

The caveat is that the layer names need to be unique, or be the first layer in the project with the actual name. If this can not be guaranteed, one needs to dig in and find the layer ids and use them instead.

There is also (of course) a plugin for filtering multiple layers: FilterLayersAtOnce. I did install it, and could have used it, but as it is either filtering everything or the selected layers, I would need to make sure I had the right layers selected each time I was using it, so I found the script easier.

I am also using postgis as the data storage and as far as I understand, the filter is working on the data provider level, so only the data with versjon=13 will be fetched from the server (although, in my case the dataset is so small it does not matter where the filtering takes place)