title: mysql - delete rows if null exist more than a specific num
body: <p>I have a table like :  </p>
  
  <pre>id | name1 | name2 | name3</pre>   
  
  <pre> 1 |  asa  |  NULL |  das</pre>  
  
  <pre> 2 |  NULL |  NULL |  asas</pre>
  
  <p>I want to delete every row that has two or more time the NULL value (here, the one with id = 2)<br>
  I already did that with a small PHP script but i wonder if that can be done with a mysql query  </p>
  
  <p>I am new to mysql so i didn't try anything yet!</p>