[lab-mysql-select] Elora Kerboua

your-code/solutions.sql

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+USE lab_mysql_select;
+
+-- CHALLENGE 1 : Who Have Published What At Where?
+SELECT * FROM authors;
+
+SELECT 
+    au.au_id AS 'AUTHOR ID',
+    au.au_lname AS 'LAST NAME',
+    au.au_fname AS 'FIRST NAME',
+    t.title AS 'TITLE',
+    pub.pub_name AS 'PUBLISHER'
+FROM 
+    authors au
+JOIN 
+    titleauthor ta ON au.au_id = ta.au_id
+JOIN 
+    titles t ON ta.title_id = t.title_id
+JOIN 
+    publishers pub ON t.pub_id = pub.pub_id;
+
+SELECT COUNT(*) AS 'TOTAL RECORDS IN TITLEAUTHOR' FROM titleauthor;
+
+-- CHALLENGE 2 : Who Have Published How Many At Where?
+
+SELECT 
+    au.au_id AS 'AUTHOR ID',
+    au.au_lname AS 'LAST NAME',
+    au.au_fname AS 'FIRST NAME',
+    pub.pub_name AS 'PUBLISHER',
+    COUNT(ta.title_id) AS 'TITLE COUNT'
+FROM 
+    authors au
+JOIN 
+    titleauthor ta ON au.au_id = ta.au_id
+JOIN 
+    titles t ON ta.title_id = t.title_id
+JOIN 
+    publishers pub ON t.pub_id = pub.pub_id
+GROUP BY 
+    au.au_id, pub.pub_name;
+
+-- CHALLENGE 3 : Best Selling Authors
+SELECT 
+    au.au_id AS 'AUTHOR ID',
+    au.au_lname AS 'LAST NAME',
+    au.au_fname AS 'FIRST NAME',
+    SUM(title_counts) AS 'TOTAL'
+FROM 
+    authors au
+JOIN (
+    SELECT 
+        ta.au_id,
+        COUNT(ta.title_id) AS title_counts
+    FROM 
+        titleauthor ta
+    GROUP BY 
+        ta.au_id
+) AS title_counts_subquery ON au.au_id = title_counts_subquery.au_id
+GROUP BY 
+    au.au_id, au.au_lname, au.au_fname
+ORDER BY 
+    TOTAL DESC
+LIMIT 3;
+
+-- CHALLENGE 4 : Best Selling Authors Ranking
+SELECT 
+    au.au_id AS 'AUTHOR ID',
+    au.au_lname AS 'LAST NAME',
+    au.au_fname AS 'FIRST NAME',
+    COALESCE(SUM(title_counts), 0) AS 'TOTAL'
+FROM 
+    authors au
+LEFT JOIN (
+    SELECT 
+        ta.au_id,
+        COUNT(ta.title_id) AS title_counts
+    FROM 
+        titleauthor ta
+    GROUP BY 
+        ta.au_id
+) AS title_counts_subquery ON au.au_id = title_counts_subquery.au_id
+GROUP BY 
+    au.au_id, au.au_lname, au.au_fname
+ORDER BY 
+    TOTAL DESC;