title: How to convert Datetime to Timestamp in SSIS
body: <p>I'm new in SSIS. I'm importing an Excel Sheet to Transform and record in another Data Source. In the Transform process I need to convert some imported DateTime to their timestamp value</p>
  
  <p>I always find Unix TimeStamp to DateTime in google search.</p>
  
  <p>I'm using a derived column component. </p>
  
  <p>I've tried this three expressions without any success:</p>
  
  <pre><code>DATEADD("ss",0,[DateToConvert])
  
  DATEDIFF("ss",(DT_DBTIME)"1970-01-01",[DateToConvert])
  
  (DT_DBTIMESTAMP)[DateToConvert]`
  </code></pre>
  
  <p>I Expect the output of <code>1571097600</code> for <code>15/10/2019</code></p>
  
  <p>Thanks in advance</p>