db.user_profile.find({ $where: "this.disk_rack.length > 1" } )但是这种js引擎执行的会非常慢
更好的办法是
CreateextrafieldNamesArrayLength, update it with names array length and then use in queries:
db.accommodations.find({"NamesArrayLength": {$gt: 1} });
It will be better solution, and will work much faster (you can create index on it).