title: Delete rows where all columns (except ID) are NULL
body: <p>I have some big tables with 100-300 columns, and sometimes an item is full of null values, leaving only the ID, like this : </p>
  
  <pre><code>|---------------------|------------------|------------------|     |------------------|
  |          ID         |     Column 1     |     Column 2     | ....|    Column 300    |
  |---------------------|------------------|------------------|     |----------------- |
  |          1          |      value       |       value      | ....
  |---------------------|------------------|------------------|
  |          2          |       NULL       |        NULL      | ....
  |---------------------|------------------|------------------|
  |          3          |       NULL       |        NULL      | ....
  |---------------------|------------------|------------------|
  </code></pre>
  
  <p>so i want to delete those but the only way i can think of is a large chunk of<br>
   <code>CASE (colA IS NULL and colB IS NULL AND colC IS NULL ...)</code>
  But that is impractical for me since there are a lot of tables with a lot of columns.</p>
  
  <p>Is there a way to delete every row which, except from the ID column, contains only NULLS?</p>