問題描述

我想獲取條件匹配的表中的第一行:

I want to get the first row in table where condition matches:

User::where('mobile', Input::get('mobile'))->first()

效果很好，但如果條件不匹配，則會(huì)拋出異常:

It works well, but if the condition doesn't match, it throws an Exception:

ErrorException
Trying to get property of non-object

目前我是這樣解決的:

if (User::where('mobile', Input::get('mobile'))->exists()) {
    $user = User::where('mobile', Input::get('mobile'))->first()
}

我可以在不運(yùn)行兩個(gè)查詢的情況下執(zhí)行此操作嗎?

Can I do this without running two queries?

推薦答案

注意:first() 方法不會(huì)像原始問題中描述的那樣拋出異常.如果您收到此類異常，則說明您的代碼中存在另一個(gè)錯(cuò)誤.

使用 first() 并檢查結(jié)果的正確方法:

The correct way to user first() and check for a result:

$user = User::where('mobile', Input::get('mobile'))->first(); // model or null
if (!$user) {
   // Do stuff if it doesn't exist.
}

其他技術(shù)(不推薦，不必要的開銷):

Other techniques (not recommended, unnecessary overhead):

$user = User::where('mobile', Input::get('mobile'))->get();

if (!$user->isEmpty()){
    $firstUser = $user->first()
}

或

try {
    $user = User::where('mobile', Input::get('mobile'))->firstOrFail();
    // Do stuff when user exists.
} catch (ErrorException $e) {
    // Do stuff if it doesn't exist.
}

或

// Use either one of the below. 
$users = User::where('mobile', Input::get('mobile'))->get(); //Collection

if (count($users)){
    // Use the collection, to get the first item use $users->first().
    // Use the model if you used ->first();
}

每種方法都是獲得所需結(jié)果的不同方式.

Each one is a different way to get your required result.

這篇關(guān)于Eloquent ->first() 如果 ->exists()的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！