title: CAST on where clause performance. Should we cast datetime string input?
body: <p>Should we use <strong><code>CAST</code></strong> for compare a date like on query below? </p>
  
  <p>On this discussion <a href="https://stackoverflow.com/questions/8076236/mysql-between-operator-with-dates">mysql between operator with dates</a> said it's better to convert your parameter STRING to DATE, but isn't mysql function in WHERE clause will make performance slower?</p>
  
  <pre><code>SELECT * from tableA WHERE datetimecolumn = CAST('2014-10-12' AS DATE)
  </code></pre>