title: Query of set time range relative to current date
body: <p>I come in to work 6.30am, and need to audit what happened from 5pm when I left to 6.30am this morning. I have used code to search 13.5 hours back from any given time:</p>
  
  <pre><code>SELECT * FROM TRANSACTION_HISTORY
  WHERE TRANSACTION_HISTORY.ACTIVITY_DATE_TIME &gt; (SELECT DATEADD(hour,-13.5,(SELECT MAX (TRANSACTION_HISTORY.ACTIVITY_DATE_TIME) FROM TRANSACTION_HISTORY)))
  </code></pre>
  
  <p>Problem is if I run query later, I lose time from the start, eg. If I run query at 7am, I only get results from 5.30pm onwards. Rather than change criteria every day, I wanted to able to search from 6.30am of the current day, back to 5.30pm of the previous day. Can this be done?</p>