Combining array_merge with perPage

Hi Tim

Thanks for posting.  What you'll need here is "usort()". 

You can read up on "usort()" in the PHP docs here: http://php.net/manual/en/function.usort.php

Also, I based most of this post on code I found in this thread on StackOverflow:

http://stackoverflow.com/questions/2910611/php-sort-a-multidimensional-array-by-element-containing-date

Let's go over an example.

First, load the records from our tables:

// load records from 'list 1'
  list($list1Records) = getRecords(array(
    'tableName'   => 'sample_multi_record',
    'loadUploads' => true,
    'allowSearch' => false,
    'limit'       => 12,
    'orderBy'     => "createdDate DESC",
  ));
  
   // load records from 'list 2'
  list($list2Records) = getRecords(array(
    'tableName'   => 'another_multi_section',
    'loadUploads' => true,
    'allowSearch' => false,
    'limit'       => 12,
    'orderBy'     => "createdDate DESC",
  ));
  
    // load records from 'list 3'
  list($list3Records) = getRecords(array(
    'tableName'   => 'yet_another_multi_section',
    'loadUploads' => true,
    'allowSearch' => false,
    'limit'       => 12,
    'orderBy'     => "createdDate DESC",
  ));

Notice how I am sorted by "createdDate DESC" and using "limit 12" in all three.  This way we only ever get a max of 12 records from each table and they are already kind of sorted.

Next, let's merge all the arrays together using array_merge() like this:

// merge arrays
$mergedList1AndList2AndList3 = array_merge($list1Records,$list2Records,$list3Records);


Next, time to sort the merged array

// sort merged arrays
usort($mergedList1AndList2AndList3, 'date_compare');
  
## compare two dates
## if returned value is positibe $a was the larger date
## if returned value is negative $b was the larger date
function date_compare($a, $b)
{
  $t1 = strtotime($a['createdDate']);
  $t2 = strtotime($b['createdDate']);
  return $t2 - $t1;
}

Notice how usort() uses a callback function to do the actual sorting. 

The last thing will be to reduce the merged and sorted list to the first 12 records using array_slice().

// only need first 12 elements from merged and sorted list
$first12Records = array_slice($mergedList1AndList2AndList3, 0, 12);

Now you have an array called "first12Records" that contains 12 records taken from three different sections and sorted by "createdDate".

Does that all make sense?  

Give it a shot and let me know how you make out.