diff --git a/.DS_Store b/.DS_Store
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index 0000000..66f57b4
Binary files /dev/null and b/.DS_Store differ
diff --git a/your-code/solutions.sql b/your-code/solutions.sql
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--- /dev/null
+++ b/your-code/solutions.sql
@@ -0,0 +1,87 @@
+USE Mysql_Nhan;
+CREATE TABLE AuthorTitlePublisher AS
+SELECT
+    a.au_id AS 'AUTHOR ID',
+    a.au_lname AS 'LAST NAME',
+    a.au_fname AS 'FIRST NAME',
+    t.title AS 'TITLE',
+    p.pub_name AS 'PUBLISHER'
+FROM
+    authors a
+JOIN
+    titleauthor ON a.au_id = titleauthor.au_id
+JOIN
+    titles t ON titleauthor.title_id = t.title_id
+JOIN
+    publishers p ON t.pub_id = p.pub_id;
+SELECT * FROM AuthorTitlePublisher;
+SELECT
+    COUNT(*) AS NumRowsInAuthorTitlePublisher
+FROM
+    AuthorTitlePublisher;
+
+-- Check the number of rows in the titleauthor table
+SELECT
+    COUNT(*) AS NumRowsInTitleAuthor
+FROM
+    titleauthor;
+/*CHallenge 2*/
+SELECT
+    `AUTHOR ID`,
+    `LAST NAME`,
+    `FIRST NAME`,
+    `PUBLISHER`,
+    COUNT(`TITLE`) AS `NUMBER OF TITLES`
+FROM
+    AuthorTitlePublisher
+GROUP BY
+    `AUTHOR ID`, `LAST NAME`, `FIRST NAME`, `PUBLISHER`;
+-- Challenges 3
+SELECT
+    `AUTHOR ID`,
+    `LAST NAME`,
+    `FIRST NAME`,
+    SUM(`NUMBER OF TITLES`) AS `TOTAL TITLES SOLD`
+FROM
+    (
+        SELECT
+            `AUTHOR ID`,
+            `LAST NAME`,
+            `FIRST NAME`,
+            `PUBLISHER`,
+            COUNT(`TITLE`) AS `NUMBER OF TITLES`
+        FROM
+            AuthorTitlePublisher
+        GROUP BY
+            `AUTHOR ID`, `LAST NAME`, `FIRST NAME`, `PUBLISHER`
+    ) AS AuthorTitleCount
+GROUP BY
+    `AUTHOR ID`, `LAST NAME`, `FIRST NAME`
+ORDER BY
+    `TOTAL TITLES SOLD` DESC
+LIMIT 3;
+-- Challenges 4:
+
+SELECT
+    `AUTHOR ID`,
+    `LAST NAME`,
+    `FIRST NAME`,
+    SUM(`NUMBER OF TITLES`) AS `TOTAL TITLES SOLD`
+FROM
+    (
+        SELECT
+            `AUTHOR ID`,
+            `LAST NAME`,
+            `FIRST NAME`,
+            `PUBLISHER`,
+            COUNT(`TITLE`) AS `NUMBER OF TITLES`
+        FROM
+            AuthorTitlePublisher
+        GROUP BY
+            `AUTHOR ID`, `LAST NAME`, `FIRST NAME`, `PUBLISHER`
+    ) AS AuthorTitleCount
+GROUP BY
+    `AUTHOR ID`, `LAST NAME`, `FIRST NAME`
+ORDER BY
+    `TOTAL TITLES SOLD` DESC
+;
\ No newline at end of file