测试版本 -- 正常无报错

$num_sum = array_sum(array_column($store, 'shuliang'));  

正式版本太低 不支持 array_column 重写方法

$sum_num = array_sum($this->array_column($store,'shuliang'));

 function array_column(array &$rows, $column_key, $index_key = null) {
        $data = array();
        if (empty($index_key)) {
            foreach ($rows as $row) {
                $data[] = $row[$column_key];
            }
        } else {
            foreach ($rows as $row) {
                $data[$row[$index_key]] = $row[$column_key];
            }
        }
        return $data;
    }