让我们创建一个包含文档的集合-
> db.demo453.insertOne( ... { _id: 101, details: [ { Name: "David", Marks: 60 }, { Name: "Mike", Marks: 55} ] } ... ) { "acknowledged" : true, "insertedId" : 101 } > db.demo453.insertOne( ... { _id: 102, details: [ { Name: "Bob", Marks: 80 }, { Name: "Sam", Marks: 78} ] } ... ) { "acknowledged" : true, "insertedId" : 102 } > db.demo453.insertOne( ... { _id: 103, details: [ { Name: "Carol", Marks: 67 }, { Name: "John", Marks: 79} ] } ... ) { "acknowledged" : true, "insertedId" : 103 }
在find()
方法的帮助下显示集合中的所有文档-
> db.demo453.find();
这将产生以下输出-
{ "_id" : 101, "details" : [ { "Name" : "David", "Marks" : 60 }, { "Name" : "Mike", "Marks" : 55 } ] } { "_id" : 102, "details" : [ { "Name" : "Bob", "Marks" : 80 }, { "Name" : "Sam", "Marks" : 78 } ] } { "_id" : 103, "details" : [ { "Name" : "Carol", "Marks" : 67 }, { "Name" : "John", "Marks" : 79 } ] }
以下是基于数组过滤文档的查询-
> db.demo453.find( ... { details: { $elemMatch: {Marks: { $gte: 75 } } } } ... )
这将产生以下输出-
{ "_id" : 102, "details" : [ { "Name" : "Bob", "Marks" : 80 }, { "Name" : "Sam", "Marks" : 78 } ] } { "_id" : 103, "details" : [ { "Name" : "Carol", "Marks" : 67 }, { "Name" : "John", "Marks" : 79 } ] }