[lab-advanced-mysql] Ekraj Pokhrel

your-code/solutions.sql

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+# Use database publication:
+USE publication;
+# List all tables in publication database:
+SHOW TABLES;
+
+
+# Challenge 1 - Most Profiting Authors
+#This challenge is solved using temorary talble:
+# Calculate the royalty of each sale for each author
+CREATE TEMPORARY TABLE publication.sales_royalty
+SELECT titles.title_id,
+		authors.au_id, 
+        sales.ord_num,
+        sales.qty,
+        (titles.price * sales.qty * titles.royalty / 100 *titleauthor.royaltyper / 100) AS royalty_per_sales
+FROM publication.authors
+	INNER JOIN publication.titleauthor
+		ON authors.au_id = titleauthor.au_id
+	INNER JOIN publication.titles
+		ON titleauthor.title_id = titles.title_id
+	INNER JOIN publication.sales
+		ON sales.title_id = titles.title_id
+GROUP BY titles.title_id, authors.au_id, authors.au_fname, sales.ord_num, sales.qty;
+
+# Using the output from Step 1 as a temp table, aggregate the total royalties for each title for each author.
+
+CREATE TEMPORARY TABLE total_royalty
+SELECT title_id, au_id, SUM(royalty_per_sales) AS royalty_per_title
+FROM sales_royalty
+GROUP BY title_id, au_id;
+
+
+# Using the output from Step 2 as a temp table, calculate the total profits of each author
+# by aggregating the advances and total royalties of each title.
+SELECT au_id, sum(royalty_per_title + titles.advance) AS aggregate_royalty
+FROM total_royalty
+INNER JOIN titles
+	ON total_royalty.title_id = titles.title_id
+GROUP BY au_id
+ORDER BY aggregate_royalty DESC
+LIMIT 3;
+
+
+
+## Challenge 2 - Alternative Solution
+# Solutions using derived table
+# Here in this solutions one derived table royalty_per_title is created and inner 
+#join with the titles table to get aggregated royalty per author 
+
+SELECT 	royalty_per_title.au_id, 
+		SUM(per_title_royalty + titles.advance) AS total_royalty
+FROM publication.titles
+INNER JOIN (
+		SELECT titles.title_id,
+			authors.au_id,         
+			SUM(titles.price * sales.qty * titles.royalty / 100 *titleauthor.royaltyper / 100) AS per_title_royalty
+		FROM publication.authors
+			INNER JOIN publication.titleauthor
+				ON authors.au_id = titleauthor.au_id
+			INNER JOIN publication.titles
+				ON titleauthor.title_id = titles.title_id
+			INNER JOIN publication.sales
+				ON sales.title_id = titles.title_id
+		GROUP BY titles.title_id, authors.au_id) AS royalty_per_title
+ON titles.title_id = royalty_per_title.title_id
+GROUP BY royalty_per_title.au_id
+ORDER BY total_royalty DESC
+LIMIT 3;
+
+##  Challenge 3 -->> most_profiting_authors
+
+CREATE TABLE publication.most_profiting_authors AS SELECT
+au_id, sum(royalty_per_title + titles.advance) AS aggregate_royalty
+FROM total_royalty
+INNER JOIN publication.titles
+	ON total_royalty.title_id = titles.title_id
+GROUP BY au_id
+ORDER BY aggregate_royalty DESC;
+
+# wiew the table most_profiting_authors
+SELECT * FROM publication.most_profiting_authors;
+
+# add foreign key to table to make relations with the database:
+ALTER TABLE publication.most_profiting_authors
+ADD FOREIGN KEY (au_id) REFERENCEs authors(au_id);