Build on top of PR #755, to be merged first. Since we want every thing from osm_building_polygon (osm_id >= 0 and osm_id < 0), we can merge the two queries. Note: the obp.osm_id >= 0 on the left join only apply to the left join part.
building
Docs
Read the layer documentation at http://openmaptiles.org/schema#building

