php二维数组按某个键值排序的实例讲解

Array
(
  [0] => Array
    (
      [name] => 龙
      [age] => 2017-02-28
    )
  [1] => Array
    (
      [name] => 龙2
      [age] => 2017-03-14
    )
  [2] => Array
    (
      [name] => 小3
      [age] => 2017-05-09
    )
  [3] => Array
    (
      [name] => 龙4
      [age] => 2017-02-03
    )
  [4] => Array
    (
      [name] => 龙5
      [age] => 2017-03-23
    )
  [5] => Array
    (
      [name] => 龙6
      [age] => 21
    )
)
array_multisort(array_column($arr,'age'),SORT_DESC,$arr);
print_r($arr);

Array
(
  [0] => Array
    (
      [name] => 龙6
      [age] => 21
    )
  [1] => Array
    (
      [name] => 小3
      [age] => 2017-05-09
    )
  [2] => Array
    (
      [name] => 龙5
      [age] => 2017-03-23
    )
  [3] => Array
    (
      [name] => 龙2
      [age] => 2017-03-14
    )
  [4] => Array
    (
      [name] => 龙
      [age] => 2017-02-28
    )
  [5] => Array
    (
      [name] => 龙4
      [age] => 2017-02-03
    )
)