title: Sqlite: how to delete rows that contain null/empty strings
body: <p>First of all thanks for your help.
  I do an learning SQL, so I need some help.</p>
  
  <p>I have a Sqlite database in which some fields in a certain column contains nothing or string of spaces.</p>
  
  <p>Please How do I delete the rows containing nothing (or string of spaces) from the database?</p>
  
  <p>Thanks for your help.</p>