Exercise SQL: Creating Customer table

Hi,

When creating the customer table, the answer was the following:

CREATE TABLE customers                         

(

   customer_id INT,

   first_name varchar(255),

   last_name varchar(255),

   email_address varchar(255),

   number_of_complaints int

);

My script included "primary key" after customer_id INT.

Also, I put "unsigned" after number_of_complaints int

Shouldn't the customer_id be a Primary Key and the number of complaints be unsigned since we can't have a negative number of complaints?

My script:

CREATE TABLE Customers
(
customer_id INT PRIMARY KEY,

first_name VARCHAR(255),

last_name VARCHAR(255),

email_address VARCHAR(255),

number_of_complaints INT unsigned

);

Thank you for taking the time to read my question.