php将两个数组相同的key合并到一个数组

$arr = array(
array(
'id' => 1,
'user_name'=>'test1'
),
array(
'id' => 2,
'user_name'=>'test2'
),
array(
'id' => 3,
'user_name'=>'test3'
)
);
$arr2 = array(
array(
'id' => 1,
'shop_name'=>'shop1'
),
array(
'id' => 5,
'shop_name'=>'shop2'
),
array(
'id' => 3,
'shop_name'=>'shop3'
)
);
怎么根据2个数组id相同的一维数组，将$arr2的shop_name添加到$arr，如果没有相同的id，shop_name为空，形成如下数组：
$good_arr =array(
array(
'id' => 1,
'user_name'=>'test1',
'shop_name'=>'shop1'
),
array(
'id' => 2,
'user_name'=>'test2',
'shop_name'=>''
),
array(
'id' => 3,
'user_name'=>'test3',
'shop_name'=>'shop3'
)

);
1. foreach($arr as $k2 =>&$v2) { $v2['shop_name']='';

foreach($arr2 as $k =>$v) {

if($v2['id'] == $v['id']) {

$v2['shop_name'] = $v['shop_name'];

}

}

}

print_r($arr);

2.

$tempArr = array();foreach($arr2 as $item) $tempArr[$item['id']] = $item['shop_name'];foreach($arr as $k => $v) { if(array_key_exists($v['id'], $tempArr)) { $arr[$k]['shop_name'] = $tempArr[$v['id']]; } else { $arr[$k]['shop_name'] = ''; }}$newArr = $arr;3.

$tmp = '';foreach ($arr2 as $k) { $tmp[$k['id']] = $k; }foreach ($arr as &$v) { $sn = $tmp[$v['id']]['shop_name']; $sn = $sn ? $sn :''; $v['shop_name'] = $sn;}var_dump($arr);?>4.$shop_name = array_column($arr2, 'shop_name', 'id');//方便减少foreach

foreach($arr as $key => $item) { $exist = array_key_exists($item['id'], $shop_name); $arr[$key]['shop_name'] = $exist ? $shop_name[$item['id']] : '';}print_r($arr);