CREATE TABLE invoices (total INTEGER, customer_id VARCHAR(255)); CREATE TABLE customers (id VARCHAR(255), first_name VARCHAR(255), last_name VARCHAR(255))
What is the total amount of money spent by Lucas Mancini?
    
SQL: SELECT SUM(T2.total) FROM customers AS T1 JOIN invoices AS T2 ON T1.id = T2.customer_id WHERE T1.first_name = "Lucas" AND T1.last_name = "Mancini"