Database: dog_kennels_minus_1_0
Question: Find the owner id and zip code of the owner who spent the most money in total for his or her dogs.
SQL: select t1.owner_id , t1.zip_code from owners_dogs as t1 join treatments as t2 on t1.dog_id = t2.dog_id group by t1.owner_id order by sum ( t2.cost_of_treatment ) desc limit 1