title: Select rows that have at least one null value
body: <p>I had a database that allowed <code>NULL</code> in many of its columns (in all tables). I would like to know if there is a clean way to select from a table all the rows that have at least one value set to null in any column.</p>
  
  <p>I know that this can be achieved by using:</p>
  
  <pre><code>SELECT * FROM `my_table` WHERE `column_1` is null OR `column_2` is null ... with all columns 
  </code></pre>
  
  <p>but I want to know if there is a cleaner and more general way so I must not make a new query for every new table.
  Thanks.</p>