MongoDB哪种查询在数组中多次找到相同的值？

2026-06-04 1 花语

要多次查找相同的值，请在MongoDB中使用$where。让我们创建一个包含文档的集合-

> db.demo188.insertOne( ... { ... "ListOfData":[ ... {"Data": 100}, ... {"Data": 200}, ... {"Data": 100} ... ] ... } ...); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad1c203d395bdc21346bd") } > db.demo188.insertOne( ... { ... "ListOfData":[ ... {"Data": 100}, ... {"Data": 200}, ... {"Data": 300} ... } ...); { "acknowledged" : true, "insertedId" : ObjectId("5e3ad1c203d395bdc21346be") }

在find()方法的帮助下显示集合中的所有文档-

> db.demo188.find();

这将产生以下输出-

{ "_id" : ObjectId("5e3ad1c203d395bdc21346bd"), "ListOfData" : [ { "Data" : 100 }, { "Data" : 200 }, { "Data" : 100 } ] } { "_id" : ObjectId("5e3ad1c203d395bdc21346be"), "ListOfData" : [ { "Data" : 100 }, { "Data" : 200 }, { "Data" : 300 } ] }

以下是在数组中多次查找相同值的查询-

> db.demo188.find({ ... "$where": function() { ... return this.ListOfData.filter(function(d) { ... return d.Data == 100; ... }).length > 1; ... } ...})

这将产生以下输出-

{ "_id" : ObjectId("5e3ad1c203d395bdc21346bd"), "ListOfData" : [ { "Data" : 100 }, { "Data" : 200 }, { "Data" : 100 } ] }