title: DATEDIFF check for one minute is actually between one and two minutes
body: <p>I am using DATEDIFF to make sure a certain action cannot happen more than once a minute.</p>
  
  <pre><code>SELECT COUNT(*) 
  FROM FOOD_ACTION
  WHERE 
  DATEDIFF(MINUTE,INSERT_DT,GETDATE()) &lt;= 1
  </code></pre>
  
  <p><code>INSERT_DT</code> is a date column with the same format that <code>GETDATE()</code> returns</p>
  
  <p>If anything is returned from this query, the action is not allowed to happen.</p>
  
  <p>The thing is, it only <i>kind of</i> works. I've had it range from a minute and 10 seconds all the way up to almost two minutes before it will let the action happen again. There doesn't seem to be any consistency in if its closer to one minute or two, and I've confirmed that <code>GETDATE()</code> returns the same exact time as my application does when it sets the <code>INSERT_DT</code> column.</p>
  
  <p>What's up with the inconsistent and incorrect timing?</p>