CREATE TABLE customer (cust_name VARCHAR)
CREATE TABLE loan (cust_id VARCHAR, loan_type VARCHAR)

Find the name of customers who do not have a loan with a type of Mortgages.
SELECT cust_name FROM customer EXCEPT SELECT T1.cust_name FROM customer AS T1 JOIN loan AS T2 ON T1.cust_id = T2.cust_id WHERE T2.loan_type = 'Mortgages'
SELECT "cust_name" FROM "customer" EXCEPT SELECT "T1"."cust_name" FROM "customer" AS "T1" JOIN "loan" AS "T2" ON "T1"."cust_id" = "T2"."cust_id" AND "T2"."loan_type" = 'Mortgages'