Usercheck.php Script Request

I am looking for a script to check my database to see if a username is already in use. I am new to PHP so talk to me like I am 10 (even though a ten year old can probably program better than me). I just want to check the database and return a true or false based on a variable that is entered in my form below. Also, I want to use an AJAX request to make this happen so I don't know if that matters. Also I am using SQL Buddy.

   <p><form action="/signup/register.php" method="post">

  <label for="first_name">First Name</label>
  <input type="text" name="first_name" />

  <label for="last_name">Last Name</label>
  <input type="text" name="last_name" />

  <label for="company">Company</label>
  <input type="text" name="company" />

  <label for="job_title">Job Title</label>
  <input type="text" name="job_title" />

  <label for="phone">Phone</label>
  <input type="text" name="phone" />

  <label for="email">Email</label>
  <input type="text" name="email" />

  <label for="username">Choose a Us开发者_JAVA技巧ername</label>
  <input type="text" name="username" />

  <label for="password">Choose a Password</label>
  <input type="text" name="password" />

  <label for="confirm_password">Confirm Your Password</label>
  <input type="text" name="confirm_password" />

  <input type="submit" value="Get Started" />

  </form>

This is one of the things php is good for.

Since you say you are beginner programmer I'm going to point you to a basic tutorial on checking Databases with sql:

HP 101 (part 8): Databases and Other Animals - Part 1

This tutorial covers all you need:

• A little SQL
• MySQL connection
• Integration with a form.

In general all the PHP 101 series is really good for beginners.

If you prefer a more detailed coverage of the topic then: PHP and MySQL Web Development (4th Edition) is the best beginners book. IMO