如何删除mongodb中的N个文档 [英] How to delete N numbers of documents in mongodb

问题描述

在我的收藏中，文档包含状态和时间戳等键.当我想查找最新的十个文档时，我会编写以下查询

In my collections, documents contains key like status and timestamp. When I want to find latest ten documents then I write following query

db.collectionsname.find().sort({"timestamp"-1}).limit(10)

这个查询给了我想要的结果，但是当我想删除最新的十个文档时，我正在编写以下查询

This query gives me results which I want but when I want to delete latest ten documents then I was writing the following query

db.collectionsname.remove({"status":0},10).sort({"timestamp":-1})

但它显示以下错误TypeError:无法调用未定义的方法排序"我再次写了与下面相同的查询db.collectionsname.remove({"status":0},10)它只删除一个文档.那么如何编写一个删除十个最新文档并按时间戳排序的查询?

but it shows following error TypeError: Cannot call method 'sort' of undefined and again I wrote the same query as below db.collectionsname.remove({"status":0},10) It deletes only one document. So how can I write a query which deletes ten latest documents and sorts on timestamp?

推荐答案

在使用 remove 或 findAndModify 时不能设置限制.因此，如果您想精确限制删除的文档数量，您需要分两步完成.

You can't set a limit when using remove or findAndModify. So, if you want to precisely limit the number of documents removed, you'll need to do it in two steps.

db.collectionName.find({}, {_id : 1})
    .limit(100)
    .sort({timestamp:-1})
    .toArray()
    .map(function(doc) { return doc._id; });  // Pull out just the _ids

然后将返回的_ids传递给remove方法:

Then pass the returned _ids to the remove method:

db.collectionName.remove({_id: {$in: removeIdsArray}})

仅供参考:您不能从有上限的集合中删除文档.

FYI: you cannot remove documents from a capped collection.

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