db.getCollection('orders').aggregate([
{$group: {
_id: {name: "$name"},
uniqueIds: {$addToSet: "$_id"},
count: {$sum: 1}
}
},
{$match: {
count: {"$gt": 1}
}
}
])
First Group Query the group according to the fields.
Then we check the unique Id and count it, If count is greater then 1 then the field is duplicate in the entire collection so that thing is to be handle by $match query.