MongoDB查询仅获取特定数量的元素
要仅返回特定数量的元素，请使用aggregate()和$slice。让我们创建一个包含文档的集合-
> db.demo75.insertOne({"Name":["Sam","Mike","Carol","David","Bob","John"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e2bcd7671bf0181ecc42278")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo75.find();
这将产生以下输出-
{ "_id" : ObjectId("5e2bcd7671bf0181ecc42278"), "Name" : [ "Sam", "Mike", "Carol", "David", "Bob", "John" ] }以下是MongoDB中的切片查询-
> db.demo75.aggregate([ { $project: { Name: { $slice: [ "$Name", 4 ] } } } ]);这将产生以下输出-
{ "_id" : ObjectId("5e2bcd7671bf0181ecc42278"), "Name" : [ "Sam", "Mike", "Carol", "David" ] }