Question

I am converting PHP (v 5.2.17)-based reports to SSRS.

I’m trying to write a query that subtracts dates like the php file does.

The date calculation either matches exactly, or it differs by exactly 3600 seconds

  $timediff=strtotime(date("Y-m-d"))-strtotime("03/29/2007");
  print $timediff;  // 137635200 

  select (trunc(sysdate) - to_date('03/29/2007','MM/DD/YYYY'))*60*60*24 from dual
  -- returns 137635200 - matches


  $timediff=strtotime(date("Y-m-d"))-strtotime("11/23/2009");
  print $timediff;  // 53823600 

  select (trunc(sysdate) - to_date('11/23/2009','MM/DD/YYYY'))*60*60*24 from dual
  -- returns 53827200 - doesnt match - off by 3600

I’ve searched stackoverflow and found the following example which sounds like it (11/23/2009 is a monday, and so is today 8/8, but it doesnt differ in the same way) PHP Strtotime erratic function

My assumption is that the php calculation is wrong, and the oracle is correct.

What say you? 😉

Thanks!

Answer 1

Without seeing the exact values I suspect its because one of them is adjusting for daylight savings and the other is not. Most parts of the world change to/from daylight savings time during march. So in your first example both dates are in the same GMT offset, but in the second (November) they’re not.

So one of your platforms (probably Oracle) is taking this one hour shift into account and the other is not.