title: Rounding Oracle SYSDATE to the nearest hour
body: <p>Supposing the current SYSDATE is 03-APR-17 03.35.49, my query would need to get values between:</p>
  
  <p>a. SYSDATE rounded to nearest passed hour (in this case 03.00.00)</p>
  
  <p>b. a minus 1 hour = 02.00.00</p>
  
  <p>I have tried and found that using "-1/24" returns the date time with an hour subtracted. Kinda new to Oracle so struggling on the first part.
  Not sure if I should be using ROUND or FLOOR or any other functionality.
  Any help appreciated.</p>