I have the following problem: I want to use the OSM plugin to import data from a sqlite database that contains OSM data. In the 'Export OSM topolgy to spatialite' dialog I choose the database file and the polygon geometry. Then I click the 'Exported tags' button. This shows me the list of tags together with the count of features. In my case, I select admin_level, which has 267 features. Now I press ok. After the export, I would expect that only 267 features are inserted in the added layer. But when I check the feature count of the new layer it has about 52000 tags, which is pretty much every polygon. When I had a look at the attribute table the admin_level field has the value NULL for every feature.
When I check the 'Not Null' checkbox, the new layer is empty and has no features at all, so it seems that all values are NULL in some sense. I'm not sure to what attribute the 'not null' conditions applies. If I would know, I could cross-check it in the database.