title: Oracle Implicit Conversion of String to date?
body: <p>I work in T-SQL but have been given some Oracle PL-SQL for review on a Project.</p>
  
  <p>Within the code there are Multiple WHERE clauses that do comparison of a Field of DataType = DATE against Strings which hold a "date".</p>
  
  <p>ex:  </p>
  
  <pre><code>       WHERE to_date(mytable.mydatefield) &gt; '23-OCT-2015'
  </code></pre>
  
  <p>OR</p>
  
  <pre><code>       WHERE mytable.mydatefield &gt; '23-OCT-2015'
  </code></pre>
  
  <p>Q1:  Since "mydatefield" is already defined as a DATA type, isn't doing a "to_date" unnecessary?</p>
  
  <p>Q2:  Will Oracle do an implicit conversion on the '23-OCT-2015' and convert it to a date for comparison?  I seem to remember encountering this before and comparing DATES to STRINGS caused issues? 
  Am I incorrect about that?  If not can someone give me an example that I can use as evidence that it would not work?</p>