listo [DAPT 2022] René Navarro

solution.sql

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+select ta.au_id "AUTHOR ID", a.au_lname "LAST NAME", a.au_fname "FIRST NAME", t.title "TITLE", p.pub_name "PUBLISHER"
+from titleauthor ta
+inner join authors a on ta.au_id = a.au_id
+inner join titles t on ta.title_id = t.title_id
+inner join publishers p on t.pub_id = p.pub_id;
+
+
+-- The INNER JOIN keyword selects records that have matching values in both tables.
+select ta.au_id "AUTHOR ID", a.au_lname "LAST NAME", a.au_fname "FIRST NAME", p.pub_name "PUBLISHER", count(t.title) "TITLE COUNT"
+from titleauthor ta
+inner join authors a on ta.au_id = a.au_id
+inner join titles t on ta.title_id = t.title_id
+inner join publishers p on t.pub_id = p.pub_id
+group by ta.au_id, p.pub_id
+order by count(t.title) desc;
+
+
+-- The LEFT JOIN keyword returns all records from the left table (table1), and the matching records from the right table (table2). The result is 0 records from the right side, if there is no match.
+select a.au_id "AUTHOR ID", a.au_lname "LAST NAME", a.au_fname "FIRST NAME", count(qty) "TOTAL"
+from authors a
+left join titleauthor ta on a.au_id = ta.au_id
+left join sales s on ta.title_id = s.title_id
+group by a.au_id, a.au_lname, a.au_fname
+order by count(qty) desc
+limit 3;
+
+-- The COALESCE() function returns the first non-null value in a list.
+-- The DESC command is used to sort the data returned in descending order.
+select a.au_id "AUTHOR ID", a.au_lname "LAST NAME", a.au_fname "FIRST NAME", sum(coalesce(qty,0)) "TOTAL"
+from authors a
+left join titleauthor ta on a.au_id = ta.au_id
+left join sales s on tar.title_id = s.title_id
+group by a.au_id, a.au_fname, a.au_lname
+order by sum(coalesce(qty,0)) desc;
+