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solutions.sql

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+-- Challenge 1 - Who Have Published What At Where?
+-- In this challenge you will write a MySQL SELECT query that joins various tables to figure out what titles each author has published at which publishers. Your output should have at least the following columns:
+
+-- AUTHOR ID - the ID of the author
+-- LAST NAME - author last name
+-- FIRST NAME - author first name
+-- TITLE - name of the published title
+-- PUBLISHER - name of the publisher where the title was published
+
+USE publications; 
+
+select * from authors;
+
+-- COLUMNS: au_id , au_lname, au_fname, title, pub_name 
+-- TABLES: author, titles, titleauthor, publishers
+-- Common denominator: title_id, au_id, pub_id
+
+SELECT authors.au_id as Author, authors.au_lname as `Last Name` , authors.au_fname as `First Name` , titles.title as Title , publishers.pub_name as `Publisher Name` 
+	FROM authors
+	LEFT JOIN titleauthor
+		ON authors.au_id = titleauthor.au_id
+	LEFT join titles
+		ON titles.title_id = titleauthor.title_id
+	LEFT JOIN publishers
+		ON titles.pub_id = publishers.pub_id;
+
+-- Challenge 2 - Who Have Published How Many At Where?
+
+SELECT authors.au_id as Author, authors.au_lname as `Last Name` , authors.au_fname as `First Name` , publishers.pub_name as `Publisher Name`, count(*)
+	FROM authors
+	INNER JOIN titleauthor
+		ON authors.au_id = titleauthor.au_id
+	INNER join titles
+		ON titles.title_id = titleauthor.title_id
+	INNER JOIN publishers
+		ON titles.pub_id = publishers.pub_id
+        GROUP BY Author, `Publisher Name` 
+        ORDER BY Author DESC;
+
+-- Challenge 3 - Best Selling Authors
+
+SELECT authors.au_id as Author, authors.au_lname as `Last Name` , authors.au_fname as `First Name`, SUM(sales.qty) as Sales
+	FROM authors
+	INNER JOIN titleauthor
+		ON authors.au_id = titleauthor.au_id
+	INNER join titles
+		ON titles.title_id = titleauthor.title_id
+	INNER JOIN sales
+		ON titles.title_id = sales.title_id
+        GROUP BY Author
+        ORDER BY Sales DESC
+        LIMIT 3;
+
+-- Challenge 4 - Best Selling Authors Ranking
+SELECT authors.au_id as Author, authors.au_lname as `Last Name` , authors.au_fname as `First Name`, ifnull(SUM(sales.qty),0) as Sales
+	FROM authors
+	LEFT JOIN titleauthor
+		ON authors.au_id = titleauthor.au_id
+	LEFT join titles
+		ON titles.title_id = titleauthor.title_id
+	LEFT JOIN sales
+		ON titles.title_id = sales.title_id
+        GROUP BY Author
+        ORDER BY Sales DESC;
+