CREATE TABLE customer (cust_name VARCHAR2, acc_type VARCHAR2)

Find the name of customers who have both saving and checking account types.
SELECT cust_name FROM customer WHERE acc_type = 'saving' INTERSECT SELECT cust_name FROM customer WHERE acc_type = 'checking'
SELECT "cust_name" FROM "customer" WHERE "acc_type" = 'saving' INTERSECT SELECT "cust_name" FROM "customer" WHERE "acc_type" = 'checking'