Laravel Eloquent 按关系对结果进行分组

Question

我正在努力让 Laravel Eloquent 以我喜欢的方式检索和分组结果。

基本上我正在创建一个 'My Agenda' 页面，它按截止日期的顺序显示所有任务，但如果 2 个或更多任务（按顺序）属于同一阶段，则将它们组合在一起，同样如果 2 个或更多阶段属于同一个项目。

我的数据是项目 ->（有很多）阶段 ->（有很多）任务

我想输出我的数据如下：

Project B
    Stage 2
        Task 1 (due 1st Sep)
        Task 3 (due 2nd Sep)
    Stage 1
        Task 2 (due 3rd Sep)

Project A
    Stage 1
        Task 2 (due 4th Sep)

Project B <---- repeated as Project A has a stage->task due before these tasks due
    Stage 3
       Task 2 (due 5th Sep)


Project A  <---- repeated as Project B has a stage->task due before
    Stage 1 <---- repeated
        Task 1 (due 6th Sep)

有什么办法可以实现吗？我愿意使用 JS/Vue/Lodash.

在前端执行此操作

提前致谢！

男

Answer 1

我认为你可以这样做：

首先，让我们用 JOIN 合并所有表。如果你想查看所有没有任何关系数据的项目和阶段，你可以使用 LEFT JOIN，或者 RIGHT JOIN，我不知道哪个有效。

$tasks = Task::orderBy("due")
  ->join("stages", "stages.id", "=", task.stage_id)
  ->join("projects", "projects.id", "=", stages.project_id)
  ->select("pick the columns you want to have")
  ->get();

我认为您应该将这种类型的数组作为输出，这样您就不会因为重复的键名而遇到任何问题。

/*
$output = [
  [
    'project'=> A,
    'stages'=> [
       stage_name => [task 1, task 2],
       stage_name => [task 4, task 8],
    ],
  ],
  [
    'project'=> B,
    'stages'=> [
       stage_name => [task 5],
    ],
  ],
  [...]
];
*/

要创建这种类型的数组，下面的函数应该可以工作。

$output = [];

foreach($tasks => $task) {
   $project = $task['project_name'];
   $lastEntry = $output[count($output) - 1];
   if ( count($output) > 0 && $lastEntry['project'] == $project) {
      // this means $task should be inserted in the last array.
      // You should check for stages.
      if (array_key_exists($task['stage_name'], $lastEntry['stages'])) {
        $lastEntry['stages'][$task['stage_name']][] = $task;  
      } else {
        $lastEntry['stages'][$task['stage_name']] = [$task];
      }
      // I think $lastEntry['stages'][$task['stage_name']][] = $task; will work without checking stage names, but I can't be sure, you need to try it.
   } else {
      // This means you should create a new item in $output.
      $output[] = [
        'project' => name,
        'stages' => [
          'stage_name' => [$task];
        ]
      ]
   }
}

我直接在这里创建了那些代码。可以有错别字什么的，但逻辑应该是可行的。

Laravel Eloquent 按关系对结果进行分组

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