Among the trains running west, how many trains have three-wheeled, jagged roof cars?
west is an direction; three-wheeled refers to wheels = 3; jagged roof refers to roof = 'jagged'
SELECT SUM(CASE WHEN T2.direction = 'west' THEN 1 ELSE 0 END)as count FROM cars AS T1 INNER JOIN trains AS T2 ON T1.train_id = T2.id WHERE T1.wheels = 3 AND T1.roof = 'jagged'
database name:db_id trains
cars table cars Cols: id dtype integer, train id dtype integer, position dtype integer, shape dtype text, length dtype text, sides dtype text, roof dtype text, wheels dtype integer, load_shape dtype text, load number dtype integer, 
trains table trains Cols: id dtype integer, direction dtype text, 
