mysql函数 取出指定字段重新组成一维数组

array_column（）；

$a = array(
  array(
    'id' => 5698,
    'first_name' => 'Bill',
    'last_name' => 'Gates',
  ),
  array(
    'id' => 4767,
    'first_name' => 'Steve',
    'last_name' => 'Jobs',
  ),
  array(
    'id' => 3809,
    'first_name' => 'Mark',
    'last_name' => 'Zuckerberg',
  )
);

$last_names = array_column($a, 'last_name');
print_r($last_names);

//输出
Array
(
  [0] => Gates
  [1] => Jobs
  [2] => Zuckerberg
)