从多个数据库创建视图

Question

我学习了如何使用db.siblingsDB和db.sisterDB。但我不能同时使用它们来创建来自不同数据库的视图。

我尝试过的示例查询是：

use "database1"
var users = db.getSiblingDB("database2").getCollection("User").find({})
    db.runCommand({
        "create" : "VW_User",
        "viewOn" : users,
        "pipeline" : [ 
            {
                "$lookup" : {
                    "localField" : "loginName",
                    "foreignField" : "userList.loginName",
                    "from" : "Site",
                    "as" : "User&Site"
                }
            }, 
            {
                "$unwind" : "$User&Site"
            }, 
            {
                "$unwind" : "$User&Site.userList"
            },
            {
                "$project" : {
                    "_id" : 0,
                    "userId" : "$_id",
                    "userRole" : "$User&Site.userList.role",
                    "siteId" : "$User&Site.id",
                    "active" : "$active",
                    "connectedAtTime" : "$connectedAtTime",
                    "lastMessageTime" : "$lastMessageTime"
                }
            }
        ]
    })

但这不起作用。有人请告诉我是否可能。