title: How to check for duplicates in mysql table over multiple columns
body: <p>I have a table of baseball players(all 1000 or so), with fields:</p>
  
  <pre><code>mysql&gt; describe person;
  +-----------+-------------+------+-----+---------+----------------+
  | Field     | Type        | Null | Key | Default | Extra          |
  +-----------+-------------+------+-----+---------+----------------+
  | id        | int(11)     | NO   | PRI | NULL    | auto_increment |
  | firstname | varchar(30) | NO   |     | NULL    |                |
  | lastname  | varchar(30) | NO   |     | NULL    |                |
  +-----------+-------------+------+-----+---------+----------------+
  </code></pre>
  
  <p>But I think there are some players that have gotten added in twice. How can I go through and check for how many occurrences of a particular firstname, lastname combo?</p>