title: Using trim on empty string in where clause in ORACLE SQL
body: <p>I'm trying to figure out why the below SQL statement does not return the value do in oracle</p>
  
  <pre><code>Select 'do' from dual
  where trim('  ') = ''
  </code></pre>
  
  <p>Where as </p>
  
  <pre><code>Select 'do' from dual
  where trim(' a ')='a'
  </code></pre>
  
  <p>returns the value do.</p>