Let's select the modified GeoNames layer and open the Select features using an expression tool. We can see QGIS's expression builder, which offers a very convenient GUI with a lot of functions in the middle panel, and a small and handy description for the selected function in the left panel. We do not even have to type anything to use some of the basic queries as QGIS lists every field we can access under the Fields and Values menu. Furthermore, QGIS can also list all the unique values or just a small sample from a column by selecting it and pressing the appropriate button in the left panel:
If you are familiar with basic ...
