使用 mongo 或 mongoose 和 node.js 将字符串值聚合到每个字段的唯一字符串值数组

Question

我需要汇总“姓名”的“姓氏”和“职业”以获得结果：

{
  name: 'John',
  occupations: ['software engineer', 'qa']
  lastNames: ['Smith', 'Red', 'Doe']
}

输入

name: 'John'

mongo 中存在的文档：

{name: 'John', lastName: 'Smith', occupation: 'software engineer'}
{name: 'Steve', lastName: 'Smith', occupation: 'senior software engineer'}
{name: 'John', lastName: 'Doe', occupation: 'qa'}
{name: 'Steve', lastName: 'Doe', occupation: 'manager'}
{name: 'John', lastName: 'Red', occupation: 'software engineer'}

我从这个聚合查询开始：

Employees.aggregate([
  { $match: { name: name } },
  {
    $unwind: {
      path: '$lastName',
    },
  },
  {
    $unwind: {
      path: '$occupation',
    },
  },
  { $group: { _id: '$name' } },
]);

但这会返回一个空数组，所以我有点卡住了，因为我以前从未做过聚合。

有没有办法产生这个所需的结果？

Answer 1

会是这个：

db.collection.aggregate([
   { $match: { name: "John" } },
   {
      $group: {
         _id: "$name",
         occupations: { $addToSet: "$occupation" },
         lastNames: { $addToSet: "$lastName" },
      }
   },
   {
      $project: {
         _id: 0,
         name: "$_id",
         occupations: 1,
         lastNames: 2
      }
   }
])

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