PHP如何实现统计数据合并

<?php

/**
 * 合并统计数据
 * @param $key_column         string  统计参照字段名
 * @param $_list_column       array 统计内容字段 统计字段默认值0
 * @param mixed ...$_list_arr array 需合并统计内容
 * @return array
 */
function statArrMergeHandle($key_column, $_list_column, ...$_list_arr)
{
  //整理统计参照字段内容
  $_total_key = array();
  foreach ($_list_arr as $_arr) $_total_key = array_merge($_total_key, array_column($_arr, $key_column));
  $_total_key = array_unique($_total_key);
  sort($_total_key);


  $_return_data = array();

  //组合返回数组统计字段及内容，默认值0（根据情况自行设置默认值）
  $_modal_key = array();
  foreach ($_list_column as $_column) $_modal_key[$_column] = 0;

  foreach ($_total_key as $key => $item) {
    $_arr_key = $_modal_key;
    $_arr_key[$key_column] = $item;

    foreach ($_list_arr as $_arr) {//遍历需合并数据结果
      foreach ($_arr as $em) {
        if ($item == $em[$key_column]) {
          foreach ($_list_column as $_column) {

            //统计结果大于0，更新相应统计字段数据（判断数组内容是否存在）
            if ($em[$_column] > 0) $_arr_key[$_column] = $em[$_column];
          }
        }
      }
    }
    $_return_data[$key] = $_arr_key;
    unset($_arr_key);
  }

  return $_return_data;
}


$score_a = array(
  array('grade' => '一年级', 'sum_a' => 20),
  array('grade' => '二年级', 'sum_a' => 21),
  array('grade' => '三年级', 'sum_a' => 15),
  array('grade' => '四年级', 'sum_a' => 3),
  array('grade' => '五年级', 'sum_a' => 14)
);

$score_b = array(
  array('grade' => '一年级', 'sum_b' => 21),
  array('grade' => '二年级', 'sum_b' => 14),
  array('grade' => '四年级', 'sum_b' => 40),
  array('grade' => '五年级', 'sum_b' => 12),
  array('grade' => '六年级', 'sum_b' => 25),
);

$score_c = array(
  array('grade' => '一年级', 'sum_c' => 45),
  array('grade' => '三年级', 'sum_c' => 24),
  array('grade' => '四年级', 'sum_c' => 5),
  array('grade' => '六年级', 'sum_c' => 12)
);

$score_d = array(
  array('grade' => '一年级', 'sum_d' => 12),
  array('grade' => '二年级', 'sum_d' => 45),
  array('grade' => '六年级', 'sum_d' => 12)
);

$_last_data = statArrMergeHandle('grade', array('sum_a', 'sum_b', 'sum_c', 'sum_d'), $score_a, $score_b, $score_c, $score_d);