Select by Expression in QGIS Graphical Modeler

Question

I am trying to use select by expression or extract by expression in QGIS Graphical Modeler. I add a vector layer for input (have also tried vector features) I add the algorithm, select the input layer, then go to build the expression and there are no fields listed under Fields and Values. If I manually input the expression I get an error that the column is not found.

Answer 1

I have illustrated you an example for your problem.

I identify six steps:

1. I have a layer called "department" and I want to select the feature which has the value "Ain" in the field "nom_dep"
2. In the graphical modeler, I add a vector layer and a Select by expression algorithm. We will set up this algorithm.
3. Firstly, the input layer will be the layer chosen in the model
4. Then, I enter my expression (they find me no field as well and tell me that my expression is wrong but I know that it's right)
5. I launch the model
6. My selection went well