Table: rail_vehicles
Columns: owner
class
number_in_class
road_numbers
built

Question: What is the total number in class for the Whitehaven Coal?
SQL: SELECT SUM("number_in_class") FROM rail_vehicles WHERE "owner" = 'whitehaven coal'

Question: What was built in a class with less than 10, and the Downer Rail owner?
SQL: SELECT "built" FROM rail_vehicles WHERE "number_in_class" < 10 AND "owner" = 'downer rail'

Question: Which class has more than 15 people in the class?
SQL: SELECT "class" FROM rail_vehicles WHERE "number_in_class" > 15

Question: Who is the owner that built in 2009-2011?
SQL: SELECT "owner" FROM rail_vehicles WHERE "built" = '2009-2011'