I run into this just now. The wrong way: 

results = ActiveRecord::Base.connection.execute("select * from users limit 10")

The right way: 

results = ActiveRecord::Base.connection.exec_query("select * from users limit 10") 

Somehow the formet executes the query without returning a result. If you want to actually see the results of SELECT'ing something, use the latter query. (Which also means that you probably want to use the former for INSERT'ing, though I have not verified.)