SQL lab and ERD diagram

solutions.sql

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+-- ==========================================
+-- EXERCISE 1: BLOG DATABASE (Normalization)
+-- ==========================================
+
+
+-- 1. Create Tables(DDL)--
+
+CREATE TABLE AUTHORS(
+    author_id INT AUTO_INCREMENT PRIMARY KEY,
+    name VARCHAR(100) NOT NULL
+);
+
+CREATE TABLE INFOS(
+   info_id INT AUTO_INCREMENT PRIMARY KEY,
+   title VARCHAR(100) NOT NULL,
+   word_count INT NOT NULL,
+   views INT NOT NULL,
+   author_id INT,
+   FOREIGN KEY(author_id) REFERENCES authors(author_id)
+ );
+
+
+--2. Insert Sample Data(DML)--
+
+INSERT INTO AUTHORS (name) 
+VALUES ("Maria Charlotte"), ("Juan Perez"), ("Gemma Alcocer");
+
+INSERT INTO INFOS (author_id, title, word_count, views) 
+VALUES
+(1, "Best Paint Colors", 814, 14),             
+(2, "Small Space Decorating Tips", 1146, 221),  
+(1, "Hot Accessories", 986, 105),             
+(1, "Mixing Textures", 765, 22),               
+(2, "Kitchen Refresh", 1242, 307),  
+(1, "Homemade Art Hacks", 1002, 193),          
+(3, "Refinishing Wood Floors", 1571, 7542);
+
+--3. RESULT--
+
+SELECT a.name AS "author", i.title AS "title", i.word_count AS "word_count", i.views AS "views"
+FROM authors a LEFT JOIN infos i ON a.author_id=i.author_id;
+
+
+
+
+
+
+
+
+-- ======================================================
+-- EXERCISE 2: AIRLINE DATABASE (3NF Normalization)
+-- ======================================================
+
+-- 1. Create Tables (DDL)
+
+CREATE TABLE customers(
+   customer_id INT AUTO_INCREMENT PRIMARY KEY,
+   customer_name VARCHAR(100) NOT NULL,
+   customer_status VARCHAR(50),
+   total_customer_mileage INT
+);
+
+CREATE TABLE flights(
+   flight_id INT AUTO_INCREMENT PRIMARY KEY,
+   flight_number VARCHAR(5) NOT NULL,
+   flight_mileage INT NOT NULL,
+   aircraft_id INT,
+   FOREIGN KEY(aircraft_id) REFERENCES      aircrafts(aircraft_id)
+);
+
+
+CREATE TABLE aircrafts(
+   aircraft_id INT AUTO_INCREMENT PRIMARY KEY,
+   aircraft VARCHAR(100) NOT NULL,
+    total_seats INT NOT NULL CHECK (total_seats > 0)
+);
+
+CREATE TABLE bookings(
+   booking_id INT AUTO_INCREMENT PRIMARY KEY,
+   customer_id INT,
+   flight_id INT,
+   FOREIGN KEY(customer_id) REFERENCES customers(customer_id),
+   FOREIGN KEY(flight_id) REFERENCES flights(flight_id)
+) ;
+
+
+
+-- 2. Insert Sample Data (DML)--
+
+INSERT INTO aircrafts (aircraft, total_seats) VALUES 
+('Boeing 747', 400),
+('Airbus A330', 236),
+('Boeing 777', 264);
+
+INSERT INTO customers (customer_name, customer_status, total_customer_mileage) VALUES 
+('Agustine Riviera', 'Silver', 115235),
+('Alaina Sepulvida', 'None', 6008),
+('Tom Jones', 'Gold', 205767),
+('Sam Rio', 'None', 2653),
+('Jessica James', 'Silver', 127656),
+('Ana Janco', 'Silver', 136773),
+('Jennifer Cortez', 'Gold', 300582),
+('Christian Janco', 'Silver', 14642);
+
+INSERT INTO flights (flight_number, flight_mileage, aircraft_id) VALUES 
+('DL143', 135, 1),
+('DL122', 4370, 2),
+('DL53', 2078, 3),
+('DL222', 1765, 3),
+('DL37', 531, 1);
+
+INSERT INTO bookings (customer_id, flight_id) VALUES 
+(1, 1), (1, 2), (2, 2), (1, 1), (3, 2), 
+(3, 3), (1, 1), (4, 1), (1, 1), (3, 4), 
+(5, 1), (4, 1), (6, 4), (7, 4), (5, 2), 
+(4, 5), (8, 4);
+
+
+
+
+-- 3. RESULT--
+
+SELECT c.customer_name AS "Customer Name",c.customer_status AS "Customer Status",
+f.flight_number AS "Flight Number",a.aircraft AS "Aircraft",
+a.total_seats AS "Total Aircraft Seats", f.flight_mileage AS "Flight Mileage",c.total_customer_mileage AS "Total Customer Mileage"
+FROM customers c LEFT JOIN bookings b ON c.customer_id=b.customer_id 
+LEFT JOIN flights f ON b.flight_id=f.flight_id 
+LEFT JOIN aircrafts a ON f.aircraft_id=a.aircraft_id;
+
+
+
+
+
+
+-- ======================================================
+-- EXERCISE 3: AIRLINE DATABASE QUERIES
+-- ======================================================
+
+-- 1. Total number of flights--
+SELECT COUNT(DISTINCT flight_number) FROM flights;
+
+
+--2. Average flight distance--
+SELECT AVG(flight_mileage) FROM flights;
+
+
+--3. Average number of seats per aircraft--
+SELECT AVG(total_seats) FROM aircrafts;
+
+
+--4. Average miles flown by customers, grouped by status--
+SELECT customer_status, AVG(total_customer_mileage) FROM customers GROUP BY customer_status;
+
+
+--5.Max miles flown by customers, grouped by status--
+SELECT customer_status, MAX(total_customer_mileage) FROM customers GROUP BY customer_status;
+
+
+--6. Number of aircrafts with "Boeing" in their name--
+SELECT COUNT(*) FROM aircrafts WHERE aircraft LIKE '%Boeing%';
+
+
+--7. Flights with distance between 300 and 2000 miles--
+SELECT * FROM flights WHERE flight_mileage BETWEEN 300 AND 2000;
+
+
+--8. Average flight distance booked, grouped by customer status--
+SELECT c.customer_status, AVG(f.flight_mileage)
+FROM bookings b
+JOIN customers c ON b.customer_id = c.customer_id
+JOIN flights f ON b.flight_id = f.flight_id
+GROUP BY c.customer_status;
+
+
+--9.Most booked aircraft among Gold status members--
+SELECT a.aircraft, COUNT(*) AS total_bookings
+FROM bookings b
+JOIN customers c ON b.customer_id = c.customer_id
+JOIN flights f ON b.flight_id = f.flight_id
+JOIN aircrafts a ON f.aircraft_id = a.aircraft_id
+WHERE c.customer_status = 'Gold'
+GROUP BY a.aircraft
+ORDER BY total_bookings DESC
+LIMIT 1;
+
+
+