done

queries.md

@@ -1,37 +1,69 @@
 ![logo_ironhack_blue 7](https://user-images.githubusercontent.com/23629340/40541063-a07a0a8a-601a-11e8-91b5-2f13e4e6b441.png)
 
 # Answers
+CREATE DATABASE library;
+CREATE TABLE authors (
+    id SERIAL PRIMARY KEY,
+    name VARCHAR(100) NOT NULL,
+    nationality VARCHAR(50),
+    birth_year DATE
+);
+CREATE TABLE publishers (
+    id SERIAL PRIMARY KEY,
+    name VARCHAR(100) NOT NULL,
+    location VARCHAR(100),
+    founded_year INT
+);
+CREATE TABLE books (
+    id SERIAL PRIMARY KEY,
+    title VARCHAR(255) NOT NULL,
+    author_id INT REFERENCES authors(id),
+    publisher_id INT REFERENCES publishers(id),
+    publish_date DATE
+);
 
 ## Iteration 2 - Joins
 
 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.title, authors.name AS author_name
+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.name AS author_name, 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 books.title, authors.name AS author_name
+FROM books
+RIGHT JOIN authors ON books.author_id = authors.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 books.title, authors.name AS author_name
+FROM books
+FULL JOIN authors ON books.author_id = authors.id;
+
 ```
 
 <br>
@@ -41,31 +73,44 @@
 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.name AS publisher_name, publishers.location, 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 books.title, publishers.name AS publisher_name, publishers.location
+FROM books
+RIGHT JOIN publishers ON books.publisher_id = publishers.id;
+
 ```
 
 <br>
 
 4. Using a **FULL JOIN**, list all records from the `authors`, `books`, and `publishers` tables. The result should include all records from the three tables, even if there are no matches between them.
 
 ```sql
--- Your Query Goes Here
+SELECT books.title, authors.name AS author_name, publishers.name AS publisher_name
+FROM books
+FULL JOIN authors ON books.author_id = authors.id
+FULL JOIN publishers ON books.publisher_id = publishers.id;
+
 ```
 
 <br>