Add SQL queries for various JOIN operations in the documentation

queries.md

@@ -7,31 +7,38 @@
 1. Using an **INNER JOIN**, list all books (left table) that have an assigned author (right table). The result should include only books with assigned authors.
 
 ```sql
--- Your Query Goes Here
-```
+SELECT books.*
+FROM books
+INNER JOIN authors ON books.author_id = authors.id;```
 
 <br>
 
 2. Using a **LEFT JOIN**, list all authors (left table) and their corresponding books on the (right table). The result should include all authors, including those who don't have any books assigned.
 
 ```sql
--- Your Query Goes Here
+SELECT authors.*, books.title
+FROM authors
+LEFT JOIN books ON authors.id = books.author_id;
 ```
 
 <br>
 
 3. Using a **RIGHT JOIN**, list all books (right table) and their corresponding authors on the (left table). The result should include books without assigned authors.
 
 ```sql
--- Your Query Goes Here
+SELECT authors.name, books.*
+FROM authors
+RIGHT JOIN books ON authors.id = books.author_id;
 ```
 
 <br>
 
 4. Using a **FULL JOIN**, list all records from the `books` and `authors` tables. The result should include all details from both tables, even if there are no match.
 
 ```sql
--- Your Query Goes Here
+SELECT authors.*, books.*
+FROM authors
+FULL JOIN books ON authors.id = books.author_id;
 ```
 
 <br>
@@ -41,23 +48,29 @@
 1. Using an **INNER JOIN**, list all books (left table) and their corresponding publishers on the (right table). The result should include the book's title, publisher's name, and location.
 
 ```sql
--- Your Query Goes Here
+SELECT books.title, publishers.name AS publisher_name, publishers.location
+FROM books
+INNER JOIN publishers ON books.publisher_id = publishers.id;
 ```
 
 <br>
 
 2. Using a **LEFT JOIN**, list all publishers (left table) and any books they have published on the (right table). The result should include all publishers, including those who haven't published any books.
 
 ```sql
--- Your Query Goes Here
+SELECT publishers.*, books.title
+FROM publishers
+LEFT JOIN books ON publishers.id = books.publisher_id;
 ```
 
 <br>
 
 3. Using a **RIGHT JOIN**, list all books (right table) and their corresponding publishers on the (left table). The result should include all books, even those without a linked publisher.
 
 ```sql
--- Your Query Goes Here
+SELECT publishers.name AS publisher_name, books.*
+FROM publishers
+RIGHT JOIN books ON publishers.id = books.publisher_id;
 ```
 
 <br>