MongoDB 应用开发

查询

联结查询

示例：

db.getCollection("user").aggregate([
  {
    $lookup: {
      from: "organization",
      localField: "orgId",
      foreignField: "_id",
      as: "organization",
    },
  },
  {
    $unwind: {
      path: "$organization",
      preserveNullAndEmptyArrays: true,
    },
  },
  {
    $match: {
      "level":"A",
      "organization.type": "COM",
    },
  },
]);