db.dsa.aggregate([
{ $group:{
_id :{name :"$name",age:"$age",country:{$first:"$country"}}
}},
{ $project:{
"name":1,
"age":1,
"country":1,
"male_parent":1,
"female_parent":1,
"family_no":1,
}},
{ $out : "testinggroup2" }
], { allowDiskUse: true })
输出仅包含两个键(名称和年龄),但我想全部添加