Question
Write a SQL query for: Display customers that have neither loan nor account. create table account (account_number varchar(15) not null, branch_name varchar(15) not null, balance
Write a SQL query for:
Display customers that have neither loan nor account.
create table account
(account_number varchar(15) not null,
branch_name varchar(15) not null,
balance number not null,
primary key(account_number));
create table branch
(branch_name varchar(15) not null,
branch_city varchar(15) not null,
assets number not null,
primary key(branch_name));
create table customer
(customer_name varchar(15) not null,
customer_street varchar(12) not null,
customer_city varchar(15) not null,
primary key(customer_name));
create table loan
(loan_number varchar(15) not null,
branch_name varchar(15) not null,
amount number not null,
primary key(loan_number));
create table depositor
(customer_name varchar(15) not null,
account_number varchar(15) not null,
primary key(customer_name, account_number),
foreign key(account_number) references account(account_number),
foreign key(customer_name) references customer(customer_name));
create table borrower
(customer_name varchar(15) not null,
loan_number varchar(15) not null,
primary key(customer_name, loan_number),
foreign key(customer_name) references customer(customer_name),
foreign key(loan_number) references loan(loan_number));
Here is the solution I have:
SELECT customer_name FROM customer c WHERE NOT EXISTS ( SELECT 1 -- mostly irrelevant whatever you put here
FROM borrower b WHERE c.customer_name = b.customer_name
) AND
NOT EXISTS ( SELECT 1 -- mostly irrelevant whatever you put here FROM depositor d WHERE c.customer_name = d.customer_name
)
;
I was wondering if there was an alternate solution.
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