This is a function to sort an indexed 2D array by a specified sub array key, either ascending or descending.

It is usefull for sorting query results from a database by a particular field after the query has been returned

This function can be quite greedy. It recreates the array as a hash to use ksort() then back again

By default it will sort ascending but if you specify $reverse as true it will return the records sorted descending 

<?php

function record_sort($records, $field, $reverse=false)
{
    $hash = array();
    
    foreach($records as $record)
    {
        $hash[$record[$field]] = $record;
    }
    
    ($reverse)? krsort($hash) : ksort($hash);
    
    $records = array();
    
    foreach($hash as $record)
    {
        $records []= $record;
    }
    
    return $records;
}

// Example below

$airports = array
(
    array( "code" => "LHR", "name" => "Heathrow" ),
    array( "code" => "LGW", "name" => "Gatwick" ),
);

printf("Before: <pre>%s</pre>", print_r($airports, true));

$airports = record_sort($airports, "name");

printf("After: <pre>%s</pre>", print_r($airports, true));

?>

Example Outputs:

Before: Array
(
    [0] => Array ( [code] => LHR, [name] => Heathrow )
    [1] => Array ( [code] => LGW, [name] => Gatwick )
)

After: Array
(
    [0] => Array ( [code] => LGW, [name] => Gatwick )
    [1] => Array ( [code] => LHR, [name] => Heathrow )
)