title: delete duplicate record from same table in mysql
body: <p>I have one table named <code>tblm_customer</code>.   </p>
  
  <p>It contain field named <code>firstname</code> and <code>lastname</code>. Now I want to delete all records from the table that contain the same firstname and lastname that are already in the table. </p>
  
  <p>I used mysql database and <code>customerid</code> is the primary key in the table.</p>