filteropenstreetmapqgisquery
I have a table osm_roads that has a column named geometry geometry geometry(LineString,900913).
If I want to filter a city to draw districts, I cannot do it by geographic coordinates.
What if in QGIS I want to select by bounding box, such a table as that?
I had the same exact problem! After an hour of screwing around:
I know this is a couple months late, and you probably have it figured out, but I hope this helps someone! I could not find any answers in the tutorials for this one.
If this is about Select features using an Expression 
function, please try examples below:
House
"category_2" = attribute(get_feature('Test', 'ID', '1'), 'category_1')
Building
"category_3" = attribute(get_feature('Test', 'ID', '1'), 'category_1')
Best Answer
To do the bounding box you need a polygon of the city in the same coordinate system as your current data
Go to either Vector>Research Tools->Select by location or Plugins>Spatial Query and select the options.
Vector>Research Tools->Polygon from layer extent and make a polygon of the full extent. Then follow the steps in option 1 above using your new polygon.