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法律研究如何在 MongoDB 中执行升序排序？
要按升序排序，语法如下 −
db.yourCollectionName.find().sort({yourField:1});为了理解这一概念，我们来创建一个带有文档的集合。创建带有文档的集合的查询如下 −
> db.sortingDemo.insertOne({"Value":100});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8f8e2ed3c9d04998abf006")
}
> db.sortingDemo.insertOne({"Value":1});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8f8e31d3c9d04998abf007")
}
> db.sortingDemo.insertOne({"Value":150});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8f8e34d3c9d04998abf008")
}
> db.sortingDemo.insertOne({"Value":250});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8f8e37d3c9d04998abf009")
}
> db.sortingDemo.insertOne({"Value":5});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8f8e3bd3c9d04998abf00a")
}
> db.sortingDemo.insertOne({"Value":199});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8f8e3ed3c9d04998abf00b")
}
> db.sortingDemo.insertOne({"Value":243});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8f8e44d3c9d04998abf00c")
}
> db.sortingDemo.insertOne({"Value":290});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8f8e48d3c9d04998abf00d")
}使用 find() 方法从集合中显示所有文档。查询如下 −
> db.sortingDemo.find().pretty();
以下是输出 −
{ "_id" : ObjectId("5c8f8e2ed3c9d04998abf006"), "Value" : 100 }
{ "_id" : ObjectId("5c8f8e31d3c9d04998abf007"), "Value" : 1 }
{ "_id" : ObjectId("5c8f8e34d3c9d04998abf008"), "Value" : 150 }
{ "_id" : ObjectId("5c8f8e37d3c9d04998abf009"), "Value" : 250 }
{ "_id" : ObjectId("5c8f8e3bd3c9d04998abf00a"), "Value" : 5 }
{ "_id" : ObjectId("5c8f8e3ed3c9d04998abf00b"), "Value" : 199 }
{ "_id" : ObjectId("5c8f8e44d3c9d04998abf00c"), "Value" : 243 }
{ "_id" : ObjectId("5c8f8e48d3c9d04998abf00d"), "Value" : 290 }以下是按升序获取结果的查询
> db.sortingDemo.find().sort({Value:1});以下是输出 −
{ "_id" : ObjectId("5c8f8e31d3c9d04998abf007"), "Value" : 1 }
{ "_id" : ObjectId("5c8f8e3bd3c9d04998abf00a"), "Value" : 5 }
{ "_id" : ObjectId("5c8f8e2ed3c9d04998abf006"), "Value" : 100 }
{ "_id" : ObjectId("5c8f8e34d3c9d04998abf008"), "Value" : 150 }
{ "_id" : ObjectId("5c8f8e3ed3c9d04998abf00b"), "Value" : 199 }
{ "_id" : ObjectId("5c8f8e44d3c9d04998abf00c"), "Value" : 243 }
{ "_id" : ObjectId("5c8f8e37d3c9d04998abf009"), "Value" : 250 }
{ "_id" : ObjectId("5c8f8e48d3c9d04998abf00d"), "Value" : 290 }
更新日期: 2019 年 7 月 30 日
198 次浏览
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