二维数组，算法

$ar = array (
  0 => array (
    'employee_id' => '26',
    'yeji' => '60',
  ),
  1 => array (
    'employee_id' => '25',
    'yeji' => '105',
  ),
  2 => array (
    'employee_id' => '26',
    'yeji' => '100',
  ),
  3 => array (
    'employee_id' => '25',
    'yeji' => '0',
  ),
);

$res = array();
foreach($ar as $item) {
  $res[$item['employee_id']]['employee_id'] = $item['employee_id'];
  @$res[$item['employee_id']]['yeji'] += $item['yeji'];
}
print_r(array_values($res));

Array
(
    [0] => Array
        (
            [employee_id] => 26
            [yeji] => 160
        )

    [1] => Array
        (
            [employee_id] => 25
            [yeji] => 105
        )

)

$arr = array (
  0 => array (
    'employee_id' => '26',
    'yeji' => '60',
  ),
  1 => array (
    'employee_id' => '25',
    'yeji' => '105',
  ),
  2 => array (
    'employee_id' => '26',
    'yeji' => '100',
  ),
  3 => array (
    'employee_id' => '25',
    'yeji' => '0',
  ),
);
$item=array();
foreach($arr as $k=>$v){
    if(!isset($item[$v['employee_id']])){
        $item[$v['employee_id']]['employee_id']=$v['employee_id'];
        $item[$v['employee_id']]['yeji']=$v['yeji'];
    }else{
        $item[$v['employee_id']]['yeji']+=$v['yeji'];
    }
}
print_r($item);

Array
(
    [26] => Array
        (
            [employee_id] => 26
            [yeji] => 160
        )

    [25] => Array
        (
            [employee_id] => 25
            [yeji] => 105
        )

)

function calcArrSameId($arr=array())
{
	foreach ($arr as $key => $value) {
		//print_r($value);die;
		if(!isset($tmp[$value['employee_id']]))
		{
			$tmp[$value['employee_id']]['employee_id'] = $value['employee_id'];
			$tmp[$value['employee_id']]['yeji'] = $value['yeji'];
		}else{
			$tmp[$value['employee_id']]['yeji'] += $value['yeji'];
		}
		
	}
	$list = array_values($tmp);
	print_r($list);exit;
}