title: Mysql - Alter table statement to create unique index on long text field
body: <p>I'm trying to create an <code>Alter</code> command to create an <code>unique_index</code> on the first 8000 characters.  I'm not able to figure out how to add the 8000 part.  Any help would be appreciated.  Thanks!</p>
  
  <pre><code>ALTER TABLE nextractor.tblhtml
    ADD UNIQUE INDEX uniqueindex_InnerHTML (InnerHtml);
  </code></pre>