Независимый подзапрос
SELECT Cust_Name
FROM Customer_Details
WHERE Cust_ID
IN
(SELECT Cust_ID
FROM Customer_Loan)
AND Cust_ID IN
(SELECT Cust_ID
FROM Customer_Fixed_Deposit);
Коррелированный подзапрос
SELECT Cust_ID
FROM Customer_Details
WHERE Cust_ID
IN
(SELECT Cust_ID
FROM Customer_Loan
WHERE Customer_Loan.Cust_ID = Customer_Details.Cust_ID)
AND Cust_ID IN
(SELECT Cust_ID
FROM Customer_Fixed_Deposit
WHERE Customer_Fixed_Deposit.Cust_ID = Customer_Details.Cust_ID);
Мы должны найти клиентов, которые выбрали кредит, а также FD.