我在这样的子文档中有数组{"_id":ObjectId("512e28984815cbfcb21646a7"),"descDay":[{"language":"en","desc":"daydescription"},{"language":"es","desc":"descripciondeldia"}]}我想按语言过滤子文档。我可以这样做db.test.aggregate([{$project:{descDay:{$filter:{input:'$list',as:'item',cond:{$gt:['$$item.language','en']}}}}}])那会给我类似的东西{"