DatabaseManagementSystems/Practical/Assignment-A2/Queries-A2.md

Database Queries for Assignment-A2

This file contains all the queries required to build the database

Creating database

CREATE DATABASE Database_A2;
USE Database_A2;

Creating tables and specify primary keys:

CREATE TABLE Account (
  acc_no INT,
  branch_name VARCHAR(255),
  balance INT,
  PRIMARY KEY (acc_no)
);

CREATE TABLE Branch (
  branch_name VARCHAR(255),
  branch_city VARCHAR(255),
  assets INT,
  PRIMARY KEY (branch_name)
);

CREATE TABLE Customer (
  cust_name VARCHAR(255),
  cust_street VARCHAR(255),
  cust_city VARCHAR(255),
  PRIMARY KEY (cust_name)
);

CREATE TABLE Depositor (
  cust_name VARCHAR(255),
  acc_no INT
);

CREATE TABLE Loan (
  loan_no INT,
  branch_name VARCHAR(255),
  amount INT,
  PRIMARY KEY (loan_no)
);

CREATE TABLE Borrower (
  cust_name VARCHAR(255),
  loan_no INT
);

Altering tables to specify foreign keys

ALTER TABLE Account ADD FOREIGN KEY (branch_name) REFERENCES Branch (branch_name);
ALTER TABLE Depositor ADD FOREIGN KEY (cust_name) REFERENCES Customer (cust_name);
ALTER TABLE Depositor ADD FOREIGN KEY (acc_no) REFERENCES Account (acc_no);
ALTER TABLE Loan ADD FOREIGN KEY (branch_name) REFERENCES Branch (branch_name);
ALTER TABLE Borrower ADD FOREIGN KEY (cust_name) REFERENCES Customer (cust_name);
ALTER TABLE Borrower ADD FOREIGN KEY (loan_no) REFERENCES Loan (loan_no);

Adding data

INSERT INTO Branch (branch_name, branch_city, assets) VALUES
('Akurdi', 'Pune', 5000000),
('Nigdi', 'Pune', 3000000),
('Kharadi', 'Pune', 4000000),
('Hadapsar', 'Pune', 3500000),
('Viman Nagar', 'Pune', 4500000);

INSERT INTO Account (acc_no, branch_name, balance) VALUES
(101, 'Akurdi', 15000),
(102, 'Nigdi', 8000),
(103, 'Kharadi', 20000),
(104, 'Hadapsar', 12000),
(105, 'Viman Nagar', 5000);

INSERT INTO Customer (cust_name, cust_street, cust_city) VALUES
('Kalas', 'Street 1', 'Pune'),
('Mehul', 'Street 2', 'Pune'),
('Tanmay', 'Street 3', 'Pune'),
('Kshitij', 'Street 4', 'Pune'),
('Aditya', 'Street 5', 'Pune');

INSERT INTO Depositor (cust_name, acc_no) VALUES
('Kalas', 101),
('Mehul', 102),
('Tanmay', 103),
('Kshitij', 101),
('Aditya', 104);

INSERT INTO Loan (loan_no, branch_name, amount) VALUES
(201, 'Akurdi', 15000),
(202, 'Nigdi', 13000),
(203, 'Kharadi', 25000),
(204, 'Hadapsar', 18000),
(205, 'Akurdi', 1400);

INSERT INTO Borrower (cust_name, loan_no) VALUES
('Mehul', 202),
('Tanmay', 203),
('Aditya', 205);

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Running queries

1. Find the names of all branches in loan relation.

SELECT DISTINCT branch_name FROM Loan;

2. Find all loan numbers for loans made at Akurdi Branch with loan amount > 12000.

SELECT loan_no FROM Loan WHERE branch_name = 'Akurdi' AND amount > 12000;

3. Find all customers who have a loan from bank. Find their names,loan_no and loan amount.

SELECT * from Borrower;
SELECT Borrower.cust_name, Borrower.loan_no, Loan.amount FROM Borrower INNER JOIN Loan ON Borrower.loan_no = Loan.loan_no;

4. List all customers in alphabetical order who have loan from Akurdi branch.

SELECT cust_name FROM Borrower INNER JOIN Loan ON Borrower.loan_no = Loan.loan_no WHERE branch_name = 'Akurdi' ORDER BY cust_name;

5. Find all customers who have an account or loan or both at bank.

SELECT cust_name FROM Depositor UNION SELECT cust_name FROM Borrower;

6. Find all customers who have both account and loan at bank.

SELECT cust_name FROM Depositor INTERSECT SELECT cust_name FROM Borrower;

7. Find all customers who have account but no loan at the bank.

SELECT cust_name FROM Depositor WHERE cust_name NOT IN (SELECT cust_name FROM Borrower);

-- OR YOU CAN RUN THE BELOW COMMAND IF YOU ARE FEELING FANCY
-- SELECT Customer.cust_name FROM Customer INNER JOIN Depositor ON Customer.cust_name = Depositor.cust_name LEFT JOIN Borrower ON Customer.cust_name = Borrower.cust_name WHERE Borrower.cust_name IS NULL;

8. Find the average account balance at each branch

SELECT branch_name, AVG(balance) FROM Account GROUP BY branch_name;

9. Find no. of depositors at each branch.

SELECT branch_name, COUNT(*) FROM Account INNER JOIN Depositor ON Account.acc_no = Depositor.acc_no GROUP BY branch_name;

10. Find name of Customer and city where customer name starts with Letter K.

SELECT cust_name, cust_city FROM Customer WHERE cust_name LIKE 'K%';

11. Display distinct cities of branch.

SELECT DISTINCT branch_city FROM Branch;

12. Find the branches where average account balance > 1200

SELECT branch_name FROM Account GROUP BY branch_name HAVING AVG(balance) > 12000;

13. Find number of tuples in customer relation.

SELECT COUNT(*) FROM Customer;

14. Calculate total loan amount given by bank.

SELECT SUM(amount) FROM Loan;

15. Delete all loans with loan amount between 1300 and 1500.

DELETE FROM Borrower WHERE loan_no IN (SELECT loan_no FROM Loan WHERE amount BETWEEN 1300 AND 1500);
DELETE FROM Loan WHERE amount BETWEEN 1300 AND 1500;

16. Delete all tuples at every branch located in Nigdi.

DELETE FROM Borrower WHERE loan_no IN (SELECT loan_no FROM Loan WHERE branch_name = 'Nigdi');
DELETE FROM Loan WHERE branch_name = 'Nigdi';
DELETE FROM Depositor WHERE acc_no IN (SELECT acc_no FROM Account WHERE branch_name = 'Nigdi');
DELETE FROM Account WHERE branch_name = 'Nigdi';
DELETE FROM Branch WHERE branch_name = 'Nigdi';

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