initial

Author: pritesh2000

Music_Store_database.sql

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+-- easy 1
+
+-- Q1 : Who is the senior most employee based on job title ? 
+
+SELECT * 
+FROM employee
+ORDER BY levels DESC
+LIMIT 1
+
+-- Q2 : Which countries have the most invoices ? 
+
+SELECT COUNT(*), billing_country
+FROM invoice
+GROUP BY billing_country
+ORDER BY COUNT(*) DESC
+
+-- Q3 : What are top 3 values of total invoice ?
+
+SELECT total
+FROM invoice
+ORDER BY total DESC
+LIMIT 3
+
+-- Q4: Which city has the best customers? We would like to throw a 
+-- promotional Music Festival in the city we made the most money. Write a 
+-- query that returns one city that has the highest sum of invoice totals. 
+-- Return both the city name & sum of all invoice totals
+
+SELECT billing_city, SUM(total) as invoice_total
+FROM invoice
+GROUP BY billing_city
+ORDER BY invoice_total DESC
+LIMIT 1
+
+-- Q5: Who is the best customer? The customer who has spent the most 
+-- money will be declared the best customer. Write a query that returns 
+-- the person who has spent the most money.
+
+SELECT customer.customer_id,customer.first_name, customer.last_name,SUM(total) AS money
+FROM invoice JOIN customer
+USING (customer_id)
+GROUP BY customer.customer_id
+ORDER BY money DESC
+LIMIT 1
+
+-- moderate 2
+
+-- Q1: Write query to return the email, first name, last name, & Genre 
+-- of all Rock Music listeners. Return your list ordered alphabetically 
+-- by email starting with A
+
+SELECT DISTINCT email, first_name, last_name
+FROM customer c
+JOIN invoice i ON c.customer_id = i.customer_id
+JOIN invoice_line il ON i.invoice_id = il.invoice_id
+WHERE track_id IN (
+	SELECT track_id 
+	FROM track
+	JOIN genre
+	ON genre.genre_id = track.genre_id
+	WHERE genre.name = 'Rock'
+)
+ORDER BY email
+
+-- Q2 : Let's invite the artists who have written the most rock music in 
+-- our dataset. Write a query that returns the Artist name and total 
+-- track count of the top 10 rock bands.
+
+SELECT artist.artist_id, artist.name, COUNT(artist.artist_id) AS number_of_songs
+FROM track
+JOIN album ON album.album_id = track.album_id
+JOIN artist ON artist.artist_id = album.artist_id
+JOIN genre ON genre.genre_id = track.genre_id
+WHERE genre.name = 'Rock'
+GROUP BY artist.artist_id
+ORDER BY number_of_songs DESC
+LIMIT 10
+
+
+-- Q3: Return all the track names that have a song length longer than 
+-- the average song length. Return the Name and Milliseconds for 
+-- each track. Order by the song length with the longest song listed first.
+
+SELECT name, milliseconds
+FROM track
+WHERE milliseconds > (
+	SELECT AVG(milliseconds) FROM track
+)
+ORDER BY milliseconds DESC
+
+-- advance 3
+
+-- Q1: Find how much amount spent by each customer on artists? Write a 
+-- query to return customer name, artist name and total spent
+
+WITH artists_names AS(
+	SELECT ar.artist_id AS artist_id, ar.name AS artist_name, il.invoice_id, SUM(il.unit_price * il.quantity) AS total_spent
+	FROM invoice_line il
+	JOIN track t ON t.track_id = il.track_id
+	JOIN album a ON a.album_id = t.album_id
+	JOIN artist ar ON ar.artist_id = a.artist_id
+	GROUP BY 1,3
+	ORDER BY 1,3
+)
+
+SELECT an.artist_name, c.first_name, c.last_name, SUM(an.total_spent) AS total_spent
+FROM customer c
+JOIN invoice i ON c.customer_id = i.customer_id
+JOIN artists_names an ON an.invoice_id = i.invoice_id
+GROUP BY c.customer_id, an.artist_name
+ORDER BY c.customer_id, an.artist_name
+
+
+-- Q2: We want to find out the most popular music Genre for each country. 
+-- We determine the most popular genre as the genre with the highest 
+-- amount of purchases. Write a query that returns each country along with 
+-- the top Genre. For countries where the maximum number of purchases 
+-- is shared return all Genres.
+
+WITH all_country AS(
+	
+	SELECT COUNT(il.quantity) purchases, i.billing_country AS country, g.name AS genre_name,
+	ROW_NUMBER() OVER(PARTITION BY i.billing_country ORDER BY COUNT(il.quantity) DESC) AS RowNo
+	FROM invoice_line il 
+	JOIN invoice i ON i.invoice_id = il.invoice_id
+	JOIN track t ON t.track_id = il.track_id
+	JOIN genre g ON g.genre_id = t.genre_id
+	GROUP BY 2,3
+	ORDER BY 2 ASC, 1 DESC
+)
+
+SELECT purchases, country, genre_name FROM all_country WHERE RowNo = 1
+
+
+-- Q3: Write a query that determines the customer that has spent the most 
+-- on music for each country. Write a query that returns the country along 
+-- with the top customer and how much they spent. For countries where 
+-- the top amount spent is shared, provide all customers who spent this amount
+
+WITH all_row AS(
+SELECT c.customer_id, c.first_name, c.last_name, c.country, SUM(total) AS total_invoice,
+ROW_NUMBER() OVER(PARTITION BY c.country ORDER BY SUM(total) DESC) AS row
+FROM customer c
+JOIN invoice i ON c.customer_id = i.customer_id
+GROUP BY c.customer_id, c.country
+ORDER BY c.customer_id
+)
+ 
+SELECT * FROM all_row WHERE row = 1