[I'm new to the site and my English is poor, so it is difficult for me to explain my problem. But there is no other person I can ask.]
My question is related to this exercise http://postgis.net/workshops/postgis-intro/joins.html, but it gives an error when I run it.
SELECT subways.name AS subway_name, neighborhoods.name AS neighborhood_name, neighborhoods.boroname AS borough FROM nyc_neighborhoods AS neighborhoods JOIN nyc_subway_stations AS subways ON ST_Contains(neighborhoods.geom, subways.geom) WHERE subways.name = 'Broad St';
The error is
Operation on mixed SRID geometries