如何从 Laravel 中的查询生成器获取单个值？

Question

我试图从 Laravel 中的查询生成器获取单个值，但问题是我获取的是一个数组。这是我在 Postman 中使用 dd($myVar) 的查询结果：

[{"is_liked":1}]

还有 echo($myVar):

Collection {#976
  #items: array:1 [
    0 => NewsCommentLike {#970
      #fillable: array:3 [
        0 => "user_id"
        1 => "news_comment_id"
        2 => "is_liked"
      ]
      #connection: "mysql"
      #table: "news_comment_likes"
      #primaryKey: "id"
      #keyType: "int"
      +incrementing: true
      #with: []
      #withCount: []
      #perPage: 15
      +exists: true
      +wasRecentlyCreated: false
      #attributes: array:1 [
        "is_liked" => 1
      ]
      #original: array:1 [
        "is_liked" => 1
      ]
      #changes: []
      #casts: []
      #dates: []
      #dateFormat: null
      #appends: []
      #dispatchesEvents: []
      #observables: []
      #relations: []
      #touches: []
      +timestamps: true
      #hidden: []
      #visible: []
      #guarded: array:1 [
        0 => "*"
      ]
    }
  ]
}

我的代码是：

$previous_is_liked = NewsCommentLike::query()->where(['user_id' => $user_id, 'news_comment_id' => $newsComment->id])->get(['is_liked']);

如何从 is_liked 而不是数组中获取单个值？

Answer 1

$previous_is_liked = NewsCommentLike::query()->where(['user_id' => $user_id, 'news_comment_id' => $newsComment->id])->first()->is_liked;

首先调用returns1个结果而不是数组，然后你可以调用你想要的列。

我相信你也可以这样称呼它：

$previous_is_liked = NewsCommentLike::query()->where(['user_id' => $user_id, 'news_comment_id' => $newsComment->id])->first()->value('is_liked')

Answer 2

这就是为什么你有 ->value('my_column') 方法。所以你最终会得到：

NewsCommentLike::query()
    ->where(['user_id' => $user_id, 'news_comment_id' => $newsComment->id])
    ->value('is_liked');

The advantage is that the value is retrieved directly from the database. If you call first() before it, it can be null thus break your code.

如何从 Laravel 中的查询生成器获取单个值？

How to get a single value from Query Builder in Laravel?

php

query-builder

laravel