Table schema:
CREATE TABLE visit (Total_spent INTEGER, visitor_id VARCHAR); CREATE TABLE visitor (id VARCHAR, Level_of_membership VARCHAR)

Question: What is the total ticket expense of the visitors whose membership level is 1?
SQL: SELECT SUM(t2.Total_spent) FROM visitor AS t1 JOIN visit AS t2 ON t1.id = t2.visitor_id WHERE t1.Level_of_membership = 1