[OSM-dev] Getting admin_level=* from relations to render properly

[John Smith]

I think the problem with mapnik is this query:

select way,admin_level from planet_osm_roads where "boundary"='administrative'

it just select all ways and doesn't try to limit the returned
information to distinct ways or order the results at all, and I'm not
familiar enough with pgSQL to fix it, if it was MySQL you can tell it
to group by the column you want distinct results for, but I think I
need subselects or joins to do the same thing in pgSQL...

Although you'd probably need to go a step further and order by way and
then relation, not just admin_level...