Find cid of customers who have ordered exactly the same set of products which are ordered by a customer with cid 'c0001'.

SELECT c.cid
FROM customers c, orders o, orderline ol
WHERE c.cid = o.cid AND o.oid = ol.oid AND ol.pid IN(SELECT DISTINCT ol.pid FROM customers c, orders o, orderline ol WHERE c.cid = 'c0001' AND c.cid = o.cid AND o.oid = ol.oid);
 
-- We will drop the tables in case they exist from previous runs
drop table orderline;
drop table orders;
drop table products;
drop table categories; 
drop table customers;
  
CREATE TABLE customers (
  cid           char(5),
  cname         char(15),
  phone         char(12),
  address       char(20),
  PRIMARY KEY (cid)
);
CREATE TABLE categories (
  catid         char(2),
  catname       char(12),
  PRIMARY KEY (catid)
);
CREATE TABLE products (
  pid           char(5),
  pname         char(15),
  unit          char(5),
  price         float,
  stock_qty     integer,
  catid         char(2),
  PRIMARY KEY (pid),
  FOREIGN KEY (catid) REFERENCES categories
);
CREATE TABLE orders (
  oid           char(5),
  cid           char(5),
  odate         date,
  charge_amount float,
  PRIMARY KEY (oid),
  FOREIGN KEY (cid) REFERENCES customers
);
CREATE TABLE orderline (
  lno           integer,
  oid           char(5),
  pid           char(5),
  qty           integer, 
  price         float, 
  PRIMARY KEY (oid, lno),
  FOREIGN KEY (oid) REFERENCES orders ON DELETE CASCADE,
  FOREIGN KEY (pid) REFERENCES products
);