Question

I need to work out how many different instances occur on a different day, from many different ranges. Probably best to explain it with an example.

18-JAN-09 to 21-JAN-09
19-JAN09 to 20-JAN-09
20-JAN-09 to 20-JAN-09

Using the three examples above, I need it to collect this information and display something a little like…

18th Jan: 1
19th Jan: 2
20th Jan: 3
21st Jan: 1

… I’ll be grabbing the information from an Oracle database fwiw (hence the format above ^) and there will be hundreds, maybe thousands of records, so my lame attempt to do all sorts of loops and if statements would take forever to run.

Is there any fairly simple and efficient way of doing this? I’m really not too sure where to start unfortunately…

Thanks

Answer 1

Either your DB engine or your PHP code is going to have to loop over the date range.

Here’s some PHP code to do the summation. The day counts are stored by year-month to avoid having a huge array for a wide date range.

<?php

// Get the date ranges from the database, hardcoded for example
$dateRanges[0][0] = mktime(0, 0, 0, 1, 18, 2009);
$dateRanges[0][1] = mktime(0, 0, 0, 1, 21, 2009);
$dateRanges[1][0] = mktime(0, 0, 0, 1, 19, 2009);
$dateRanges[1][1] = mktime(0, 0, 0, 1, 20, 2009);
$dateRanges[2][0] = mktime(0, 0, 0, 1, 20, 2009);
$dateRanges[2][1] = mktime(0, 0, 0, 1, 20, 2009);

for ($rangeIndex = 0; $rangeIndex < sizeof($dateRanges); $rangeIndex++)
{
  $startDate = $dateRanges[$rangeIndex][0];
  $endDate = $dateRanges[$rangeIndex][1];

  // Add 60 x 60 x 24 = 86400 seconds for each day
  for ($thisDate = $startDate; $thisDate <= $endDate; $thisDate += 86400)
  {
    $yearMonth = date("Y-m", $thisDate);
    $day = date("d", $thisDate);

    // Store the count by year-month, then by day
    $months[$yearMonth][$day]++;
  }
}

foreach ($months as $yearMonth => $dayCounts)
{
  foreach ($dayCounts as $dayNumber => $dayCount)
  {
    echo $yearMonth . "-" . $dayNumber . ": " . $dayCount . "<br>";
  }
}

?>