Specific implementation of PHP two dimensional array sorting by a field

The implementation documented in this article is similar to ORDER BY in MySQL, which was encountered in a previous project.

Requirements: Get four pieces of data from two different tables and integrate them (array_merge) into an array, then sorted in descending order according to the creation time of the data.

When this requirement is met, it is not a problem that ORDER BY can solve.So look through the PHP manual to find the following ways to take this note.

Say nothing but code, here's the list:

 
<?php 
/** 
* 2 Dimensional array sorted by a field  
*  Function: Sort in reverse order by user's age  
* @author ruxing.li 
*/ 
header('Content-Type:text/html;Charset=utf-8'); 
$arrUsers = array( 
array( 
'id' => 1, 
'name' => ' Zhang 3', 
'age' => 25, 
), 
array( 
'id' => 2, 
'name' => ' plum 4', 
'age' => 23, 
), 
array( 
'id' => 3, 
'name' => ' king 5', 
'age' => 40, 
), 
array( 
'id' => 4, 
'name' => ' Zhao 6', 
'age' => 31, 
), 
array( 
'id' => 5, 
'name' => ' yellow 7', 
'age' => 20, 
), 
); 


$sort = array( 
'direction' => 'SORT_DESC', // Sort order flag  SORT_DESC  Descending order; SORT_ASC  Ascending order  
'field' => 'age', // sort field  
); 
$arrSort = array(); 
foreach($arrUsers AS $uniqid => $row){ 
foreach($row AS $key=>$value){ 
$arrSort[$key][$uniqid] = $value; 
} 
} 
if($sort['direction']){ 
array_multisort($arrSort[$sort['field']], constant($sort['direction']), $arrUsers); 
} 

var_dump($arrUsers); 

/* 
 Output results:  

array (size=5) 
0 => 
array (size=3) 
'id' => int 5 
'name' => string ' yellow 7' (length=6) 
'age' => int 20 
1 => 
array (size=3) 
'id' => int 2 
'name' => string ' plum 4' (length=6) 
'age' => int 23 
2 => 
array (size=3) 
'id' => int 1 
'name' => string ' Zhang 3' (length=6) 
'age' => int 25 
3 => 
array (size=3) 
'id' => int 4 
'name' => string ' Zhao 6' (length=6) 
'age' => int 31 
4 => 
array (size=3) 
'id' => int 3 
'name' => string ' king 5' (length=6) 
'age' => int 40 

*/