从 Eloquent 集合中删除不匹配的条件记录答案

【问题标题】：Remove unmatched criteria records from Eloquent collection从 Eloquent 集合中删除不匹配的条件记录
【发布时间】：2021-07-15 08:58:58
【问题描述】：

我在使用 Eloquent Eager Loading 时遇到了一些问题。我添加了whereHas 以删除博客不符合评论条件但评论仍然返回空数组。我的意图是将其从 json 记录中完全删除。

怎样才能彻底去掉不符合我条件的json数据链？

我当前的代码：

User::select("id", "name", "email")
    ->with(['blog', 'blog.author', 'blog.comments' => function ($query) {
        $query->where('comment', 'John is here');
    }, 'blog.comments.owner'])
    ->whereHas('blog.comments', function ($query) {
        $query->where('comment', 'John is Here');
    })
    ->get();

我当前的 json 输出是：

{
    "id": 1,
    "name": "John Smith",
    "email": "john.smith@hotmail.com",
    "blog": [
        {
            "id": 1,
            "created_at": "2021-04-09T18:08:06.000000Z",
            "updated_at": "2021-04-09T10:33:03.000000Z",
            "title": "First Blog",
            "description": "Awesome",
            "users_id": 1,
            "cover": null,
            "author": {
                "id": 1,
                "name": "John Smith",
                "email": "john.smith@hotmail.com",
                "email_verified_at": null,
                "created_at": "2021-04-08T13:29:13.000000Z",
                "updated_at": "2021-04-08T13:29:13.000000Z",
                "role": 0
            },
            "comments": [
                {
                    "id": 1,
                    "comment": "John is here",
                    "blog_id": 1,
                    "user_id": 1,
                    "created_at": null,
                    "updated_at": null,
                    "owner": {
                        "id": 1,
                        "name": "John Smith",
                        "email": "john.smith@hotmail.com",
                        "email_verified_at": null,
                        "created_at": "2021-04-08T13:29:13.000000Z",
                        "updated_at": "2021-04-08T13:29:13.000000Z",
                        "role": 0
                    }
                }
            ]
        },
        {
            "id": 6,
            "created_at": "2021-04-12T07:41:43.000000Z",
            "updated_at": "2021-04-12T08:01:18.000000Z",
            "title": "Second Blog",
            "description": "Awesome",
            "users_id": 1,
            "cover": "images/json_1618213303.png",
            "author": {
                "id": 1,
                "name": "John Smith",
                "email": "john.smith@hotmail.com",
                "email_verified_at": null,
                "created_at": "2021-04-08T13:29:13.000000Z",
                "updated_at": "2021-04-08T13:29:13.000000Z",
                "role": 0
            },
            "comments": []
        }
    ]
}

我的预期输出是：

{
    "id": 1,
    "name": "John Smith",
    "email": "john.smith@hotmail.com",
    "blog": [
        {
            "id": 1,
            "created_at": "2021-04-09T18:08:06.000000Z",
            "updated_at": "2021-04-09T10:33:03.000000Z",
            "title": "First Blog",
            "description": "Awesome",
            "users_id": 1,
            "cover": null,
            "author": {
                "id": 1,
                "name": "John Smith",
                "email": "john.smith@hotmail.com",
                "email_verified_at": null,
                "created_at": "2021-04-08T13:29:13.000000Z",
                "updated_at": "2021-04-08T13:29:13.000000Z",
                "role": 0
            },
            "comments": [
                {
                    "id": 1,
                    "comment": "John is here",
                    "blog_id": 1,
                    "user_id": 1,
                    "created_at": null,
                    "updated_at": null,
                    "owner": {
                        "id": 1,
                        "name": "John Smith",
                        "email": "john.smith@hotmail.com",
                        "email_verified_at": null,
                        "created_at": "2021-04-08T13:29:13.000000Z",
                        "updated_at": "2021-04-08T13:29:13.000000Z",
                        "role": 0
                    }
                }
            ]
        }
    ]
}

【问题讨论】：

能否将->get() 替换为->toSql() 并共享正在运行的SQL？
select id, name, email from users where exists (select * from blogs where users.id = blogs.@98765433存在（从comments 中选择*，其中blogs.id = comments.blog_id 和comment = ?)）
我虽然会执行内连接
这有点不合我意，我的意思是，我帮不了你太多了，对不起

标签： php laravel laravel-5 eloquent eloquent-relationship

【解决方案1】：

试试这个，

User::select("id", "name", "email")
    ->with([
        'blog' => function ($query) {
            $query->whereHas('comments', function ($query) {
                $query->where('comment', 'John is Here');
            });
        }, 
        'blog.comments' => function ($query) {
            $query->where('comment', 'John is here');
        },
        'blog.author',  
        'blog.comments.owner'])
    ->get();

您也应该对blog 急切加载应用约束。您的查询仅过滤 comments 的 blog

【讨论】：

我有一个关于 eloquent 模型的问题，我如何构建一个与 eloquent 模型合并的连接查询，但输出必须将我作为集合返回。我曾尝试使用类似 "User::join("user_role","id","=","user.role_id")" 的东西，但是当有人决定更改表名时，这可能会导致另一个问题，它可能会直接崩溃整个代码。
我建议像$user->roles 那样访问相关记录，但您首先必须定义User 模型和Role 之间的多对多roles 关系。