title: How do I remove null from table columns?
body: <p>I have a database table populated with 10k rows of data. A great deal of those rows have null values in specific columns. How do I replace this null value with for instance the empty string for a string column?</p>
  
  <p>I'm looking for the <em>easiest</em> way to do this since this operation will only need to be performed <em>once</em>.</p>
  
  <p><strong>What I have tried:</strong></p>
  
  <pre><code>UPDATE tablename set mycolumn='' where mycolumn is null;
  </code></pre>
  
  <p>This gives me the following error:</p>
  
  <blockquote>
    <p>Error Code: 1175. You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column To disable safe mode, toggle the option in Preferences -> SQL Editor and reconnect.</p>
  </blockquote>
  
  <p>I am not the administrator of the database, so I cannot disable safe mode.</p>
  
  <pre><code>UPDATE tablename set mycolumn=''
    where Id in (SELECT Id FROM tablename where mycolumn is null);
  </code></pre>
  
  <p>This gives me the following error:</p>
  
  <blockquote>
    <p>Error Code: 1093. You can't specify target table 'tablename' for update in FROM clause.</p>
  </blockquote>
  
  <hr>
  
  <p><strong>Note:</strong></p>
  
  <p>In the examples above I have substituted the real tablename and column-name with placeholders.</p>