Question

我有关于问题和答案以及回答问题的用户的数据

数据

{
  text: 'question one',
  users: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
  answers: [
    { text: 'answer one', users: [2, 3, 6, 7] },
    { text: 'answer two', users: [1, 4, 3, 8, 10] },
    { text: 'answer three', users: [1, 5, 7, 9] },
    { text: 'answer four', users: [2, 4, 6, 8, 10] }
  ]
}

，我有一个用户列表：[2、3、8、9、10]。我想得到的是根据问题过滤用户数组，并根据我拥有的用户数组来回答每个问题，这样数据就应该像这样

{
  text: 'question one',
  users: [2, 3, 8, 9, 10],
  answers: [
      { text: 'answer one', users: [2, 3] },
      { text: 'answer two', users: [3, 8, 10] },
      { text: 'answer three', users: [9] },
      { text: 'answer four', users: [2, 8, 10] },
  ]
}

我如何在mongodb中获得它？

如果我可以用长度替换过滤数组

{
  text: 'question one',
  users: 4,
  answers: [
      { text: 'answer one', users: 2 },
      { text: 'answer two', users: 3 },
      { text: 'answer three', users: 1 },
      { text: 'answer four', users: 3 },
  ]
}

我找到了一种过滤有问题的用户的解决方案，但是我不能在每个答案中过滤用户

db.getCollection('questions').aggregate([{
    $project: {
        users: { 
               $setIntersection: [ [ObjectId("5d1ae16452ca833de98e9a79")],'$users']  
        },
        // cannot filter these users
        'answers.users': {
            $setIntersection: [ [ObjectId("5d1ae16452ca833de98e9a79")], '$answers.users']  

        } 


    },


}])

如何基于MongoDB中的另一个数组过滤数组

0 个答案: