node.js - Mongoose -如何对人口进行多标准排序

Question

我试图对填充有“group.name”的“角色”文档进行排序，首先在 group.name 上，然后在 role.name 上

return this.find(query, { _group: 1, name: 1, _id:0 } )
  .populate('_group', 'name -_id')
  .sort({ '_group.name': 1, name: 1 })

但它没有按预期工作，我仅根据 role.name 进行排序

ROLES:[
{"name":"NewRole"},
{"name":"NewRoleInGroup","_group":{"name":"GroupA"}},
{"_group":{"name":"GroupA"},"name":"admin"},
{"_group":{"name":"GroupA"},"name":"employee"},
{"_group":{"name":"GroupB"},"name":"employee"},
{"_group":{"name":"GroupC"},"name":"employee"},
{"_group":{"name":"GroupA"},"name":"manager"},
{"_group":{"name":"GroupB"},"name":"manager"},
{"name":"visitor"}
]

我想要的是:

ROLES:[
// NO GROUP
{"name":"NewRole"},
{"name":"visitor"}.
// GroupA
{"_group":{"name":"GroupA"},"name":"admin"},
{"_group":{"name":"GroupA"},"name":"employee"},
{"_group":{"name":"GroupA"},"name":"manager"},
{"name":"NewRoleInGroup","_group":{"name":"GroupA"}},
// GroupB
{"_group":{"name":"GroupB"},"name":"employee"},
{"_group":{"name":"GroupB"},"name":"manager"},
// GroupC
{"_group":{"name":"GroupC"},"name":"employee"}
]

感谢反馈

更新根据@Talha 评论:

使用聚合，我接近我需要的...但是，我在数组内获取组数据，在多对一关系中，在这种情况下只有一个组...如何投影group 作为数组中的第一个对象: "group": {} 或 "group": {"name"; ...，“描述”:...}？

  return this.aggregate([
    { $match: query},
    {
      $lookup: {
        from: 'groups',
        localField: '_group',
        foreignField: '_id',
        as: 'group'
      }
    }
    ,
    {
      $project: {
        'group.name': 1,
        'group.description': 1,
        name: 1,
        description: 1,
        _id: 0
      }
    },
    { $sort: { 'name': 1 } },
    { $limit: limit },
    { $skip: skip }
  ])


 ROLES: [
// NO GROUP
{"name":"NewRole","description":"NewRole description","group":[]},
{"name":"Visitor","description":"no permissions","group":[]},
// GROUP A
{"name":"NewRoleInGroup","description":"NewRoleInGroup description","group":[{"name":"GroupA","description":"Description GroupA"}]},
{"name":"admin","description":"can RW group, user","group":[{"name":"GroupA","description":"Description GroupA"}]},
{"name":"employee","description":"can R group, can read user","group":[{"name":"GroupA","description":"Description GroupA"}]},
{"name":"manager","description":"can R group, can RW user","group":[{"name":"GroupA","description":"Description GroupA"}]},
// GROUP B
{"name":"employee","description":"can R group, can read user","group":[{"name":"GroupB","description":"Description GroupB"}]},
{"name":"manager","description":"can R group, can RW user","group":[{"name":"GroupB","description":"Description GroupB"}]},
// GROUP C
{"name":"employee","description":"can R group, can read user","group":[{"name":"GroupC","description":"Description GroupC"}]}]

Answer 1

我应该使用以下函数 w 聚合:

  return this.aggregate([
    { $match: query},
    {
      $lookup: {
        from: 'groups',
        localField: '_group',
        foreignField: '_id',
        as: 'group'
      }
    },
    {
      $project: {
        group: {
          $let:{
            vars:{
              firstGroup:{
                $arrayElemAt:["$group",0]
              }
            },
            in:{
              name:"$$firstGroup.name",
              description:"$$firstGroup.description"
            }
          }
        },
        name: 1,
        description: 1,
        _id: 0
      }
    },
    { $sort: { 'group.name': 1, 'name': 1 } },
    { $limit: limit },
    { $skip: skip }
  ])
  .exec()
  .then((list) => {
    return list;
  })

这将输出正确排序的列表( 1/by group.name 2/ny role.name )，其中组不在查找输出数组中:

ROLES: [
// NO GROUP
{"name":"NewRole","description":"NewRole description","group":{}},
{"name":"Visitor","description":"no permissions","group":{}},
// GROUP A
{"name":"NewRoleInGroup","description":"NewRoleInGroup description","group":{"name":"GroupA","description":"Description GroupA"}},
{"name":"admin","description":"can RW group, user","group":{"name":"GroupA","description":"Description GroupA"}},
{"name":"employee","description":"can R group, can read user","group":{"name":"GroupA","description":"Description GroupA"}},
{"name":"manager","description":"can R group, can RW user","group":{"name":"GroupA","description":"Description GroupA"}},
// GROUP B
{"name":"employee","description":"can R group, can read user","group":{"name":"GroupB","description":"Description GroupB"}},
{"name":"manager","description":"can R group, can RW user","group":{"name":"GroupB","description":"Description GroupB"}},
// GROUP C
{"name":"employee","description":"can R group, can read user","group":{"name":"GroupC","description":"Description GroupC"}}]