使用方式
主要是用到了类的重写和容器
$users = DB::table('users')->paginate(15);


{
    "code": 200,
    "data": {
        "current_page": 1,
        "data": [
            {
                "id": 1,
                "name": "技术部",
                "description": "",
                "qr_code_path": "http://mag.com/1.jpg",
                "created_at": "2020-06-24 16:12:43",
                "updated_at": "2020-06-24 16:12:44"
            }
        ],
        "first_page_url": "http://mag.com/department?page=1",
        "from": 1,
        "last_page": 1,
        "last_page_url": "http://mag.com/department?page=1",
        "next_page_url": null,
        "path": "http://mag.com/department",
        "per_page": 10,
        "prev_page_url": null,
        "to": 1,
        "total": 1
    },
    "message": "success"
}

查看文件

laravel5\vendor\laravel\framework\src\Illuminate\Database\Eloquent\Builder.php
paginate

paginator
    /**
     * Paginate the given query.
     *
     * @param  int  $perPage
     * @param  array  $columns
     * @param  string  $pageName
     * @param  int|null  $page
     * @return \Illuminate\Contracts\Pagination\LengthAwarePaginator
     *
     * @throws \InvalidArgumentException
     */
    public function paginate($perPage = null, $columns = ['*'], $pageName = 'page', $page = null)
    {
        $page = $page ?: Paginator::resolveCurrentPage($pageName);

        $perPage = $perPage ?: $this->model->getPerPage();

        $results = ($total = $this->toBase()->getCountForPagination())
                                    ? $this->forPage($page, $perPage)->get($columns)
                                    : $this->model->newCollection();

        return $this->paginator($results, $total, $perPage, $page, [
            'path' => Paginator::resolveCurrentPath(),
            'pageName' => $pageName,
        ]);
    }

跟进：laravel5\vendor\laravel\framework\src\Illuminate\Database\Concerns\BuildsQueries.php


可以看到我用红色标出来是是返回的分页类, 用蓝色标出来是用容器加载的这个类。
继续查找这个类 laravel5\vendor\laravel\framework\src\Illuminate\Pagination\LengthAwarePaginator.php 发现组装分页数据的是这个类中toArray方法
 /**
  * Get the instance as an array.
  *
  * @return array
  */
 public function toArray()
 {
     return [
         'current_page' => $this->currentPage(),
         'data' => $this->items->toArray(),
         'first_page_url' => $this->url(1),
         'from' => $this->firstItem(),
         'last_page' => $this->lastPage(),
         'last_page_url' => $this->url($this->lastPage()),
         'next_page_url' => $this->nextPageUrl(),
         'path' => $this->path,
         'per_page' => $this->perPage(),
         'prev_page_url' => $this->previousPageUrl(),
         'to' => $this->lastItem(),
         'total' => $this->total(),
     ];
 }

刚刚上面也说这个分页类是通过容器加载的，那我们只要在容器内重新加载下这个类就行。
修改方式
先自定义一个分页类，继承上面的分页类，并重写了toArray方法。

新建文件夹及类文件

laravel5\app\Services\Common\LengthAwarePaginatorService.php
namespace App\Services\Common;
/**
 * 重写分页返回数组
 * Class LengthAwarePaginatorService
 * @package App\Services\Common
 */
class LengthAwarePaginatorService extends \Illuminate\Pagination\LengthAwarePaginator
{
    public function toArray()
    {
        return [
            'data' => $this->items->toArray(),
            'total' => $this->total(),
        ];
    }
}

然后在 laravel5\app\Providers\AppServiceProvider.php 容器内重新绑定了这个分页类的实现
<?php

namespace App\Providers;

use App\Services\Common\LengthAwarePaginatorService;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        $this->app->bind('Illuminate\Pagination\LengthAwarePaginator',function ($app,$options){
            return new LengthAwarePaginatorService($options['items'], $options['total'], $options['perPage'], $options['currentPage'] , $options['options']);
        });
    }

    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        \Schema::defaultStringLength(191);
    }
}


预览

laravel中关于分页以及转换器的使用

$paginate->transform(function ($item) use ($pkg_tag_name_key){
    return [
        'id' => $item->id,
        'tag' => $pkg_tag_name_key,
        'createtime' => $item->CreateTime,
        'status' => $item->Status,
    ];
});

使用了以上方法后，$paginate分页变量会返回以下格式的数据类型

[
    'list' => [
        [
            'id' => $item->id,
            'tag' => $pkg_tag_name_key,
            'createtime' => $item->CreateTime,
            'status' => $item->Status,
        ]
    ],
    'page' => 1,
    'total' => 1,
    'page_size' => 1
];

即可直接把$paginate对象返回。

mysql> select * from test;
+----+-------+------+-------+
| id | name  | age  | class |
+----+-------+------+-------+
|  1 | qiu   |   22 |     1 | 
|  2 | liu   |   42 |     1 | 
|  4 | zheng |   20 |     2 | 
|  3 | qian  |   20 |     2 | 
|  0 | wang  |   11 |     3 | 
|  6 | li    |   33 |     3 | 
+----+-------+------+-------+
6 rows in set (0.00 sec)

需求是找到test表中每个class里面的最大的age，则需要使用group by和max。

如下的sql查询语句，输出结果有误：

mysql> select id,name,max(age),class from test group by class;
+----+-------+----------+-------+
| id | name  | max(age) | class |
+----+-------+----------+-------+
|  1 | qiu   |       42 |     1 | 
|  4 | zheng |       20 |     2 | 
|  0 | wang  |       33 |     3 | 
+----+-------+----------+-------+
3 rows in set (0.00 sec)

虽然找到的age是最大的age，但是与之匹配的用户信息却不是真实的信息，而是group by分组后的第一条记录的基本信息。

如使用以下的语句进行查找，则可以返回真实的结果。

mysql> select * from (
    -> select * from test order by age desc limit 100000) as t
    -> group by class;
+----+-------+------+-------+
| id | name  | age  | class |
+----+-------+------+-------+
|  2 | liu   |   42 |     1 | 
|  4 | zheng |   20 |     2 | 
|  6 | li    |   33 |     3 | 
+----+-------+------+-------+
3 rows in set (0.00 sec)

值得注意的是对于mysql 5.5版本，以上查询语句中可不加limit ，对于mysql 5.7版本,需要加入limit限制，否则不生效

 

当采用laravel框架， 并想在一个复杂的原生查询的基础上用其自带的paginate实现分页，那么可以按以下格式写：

$sql = 'select * from (select * from test order by age desc limit 100000) as t group by class';

$result =  DB::table(DB::raw("($sql ) as t"))->paginate(10)

 在这里里面 $sql 充当了一个 临时表，其中可以写非常复杂的联合查询

 


文章引用：

1. https://blog.csdn.net/magicharvey/article/details/21372813?utm_source=tuicool&utm_medium=referral 

2. https://blog.csdn.net/fmyzc/article/details/81507989                 

3. https://www.jianshu.com/p/3a53c2fc57d0

    
laravel 分页  跟thinkPHP 基本类似
在下面这个例子中，传递给 paginate 方法的唯一参数是「每页」显示的项目数量。下面是每页显示 15 条数据的例子：

<?php

namespace App\Http\Controllers;

use Illuminate\Support\Facades\DB;
use App\Http\Controllers\Controller;

class UserController extends Controller
{
    /**
     * 展示应用中的所有用户
     *
     * @return Response
     */
    public function index()
    {
        $users = DB::table('users')->paginate(15);

        return view('user.index', ['users' => $users]);
    }
}


　　分页在页面上的显示为

<div class="container">
    @foreach ($users as $user)
        {{ $user->name }}
    @endforeach
</div>

{{ $users->links() }}


　　

转载于:https://www.cnblogs.com/gaojian910/p/11465687.html