Attempt#1

solutions.sql

@@ -0,0 +1,66 @@
+-- Challenge 1: List authors, their books, and publishers
+SELECT
+    a.au_id AS author_id,
+    a.au_lname AS last_name,
+    a.au_fname AS first_name,
+    t.title,
+    p.pub_name AS publisher
+FROM authors a
+JOIN titleauthor ta ON a.au_id = ta.au_id
+JOIN titles t ON ta.title_id = t.title_id
+JOIN publishers p ON t.pub_id = p.pub_id;
+
+
+-- Challenge 2: Count of books per author per publisher
+SELECT
+    a.au_id AS author_id,
+    a.au_lname AS last_name,
+    a.au_fname AS first_name,
+    p.pub_name AS publisher,
+    COUNT(t.title_id) AS TITLE_COUNT
+FROM authors a
+JOIN titleauthor ta ON a.au_id = ta.au_id
+JOIN titles t ON ta.title_id = t.title_id
+JOIN publishers p ON t.pub_id = p.pub_id
+GROUP BY a.au_id, p.pub_name
+ORDER BY TITLE_COUNT DESC;
+
+-- Validate total book count
+SELECT SUM(book_count) FROM (
+    SELECT a.au_id, p.pub_name, COUNT(t.title_id) AS book_count
+    FROM authors a
+    JOIN titleauthor ta ON a.au_id = ta.au_id
+    JOIN titles t ON ta.title_id = t.title_id
+    JOIN publishers p ON t.pub_id = p.pub_id
+    GROUP BY a.au_id, p.pub_name
+) AS book_summary;
+
+-- Check if sum matches total entries in titleauthor
+SELECT COUNT(*) FROM titleauthor;
+
+-- Challenge 3: Top 3 authors by sales
+SELECT
+    a.au_id AS author_id,
+    a.au_lname AS last_name,
+    a.au_fname AS first_name,
+    SUM(s.qty) AS total_sales
+FROM authors a
+JOIN titleauthor ta ON a.au_id = ta.au_id
+JOIN titles t ON ta.title_id = t.title_id
+JOIN sales s ON t.title_id = s.title_id
+GROUP BY a.au_id
+ORDER BY total_sales DESC
+LIMIT 3;
+
+-- Challenge 4: Total sales per author, including those with no sales
+SELECT
+    a.au_id AS author_id,
+    a.au_lname AS last_name,
+    a.au_fname AS first_name,
+    COALESCE(SUM(s.qty), 0) AS total_sales
+FROM authors a
+LEFT JOIN titleauthor ta ON a.au_id = ta.au_id
+LEFT JOIN titles t ON ta.title_id = t.title_id
+LEFT JOIN sales s ON t.title_id = s.title_id
+GROUP BY a.au_id
+ORDER BY total_sales DESC;