$data = Db::name('about_product_list')->field('id,title,count(id) as num')->group('title')->having('num > 1')->select()->toArray();
$ids_array = [];
$max_array = [];
foreach ($data as $k => $v) {
   $ids = Db::name('about_product_list')->where(['title' => $v['title']])->column('id');
   $max = max($ids);
   $max_array = array_merge($max_array, (array)$max);
   $ids_array = array_merge($ids_array, $ids);
}

$valuesOnlyInArray1 = array_diff($max_array, $ids_array);
$valuesOnlyInArray2 = array_diff($ids_array, $max_array);
$uniqueValues = array_merge($valuesOnlyInArray1, $valuesOnlyInArray2);