如何在带有查询的MongoDB文档中找到特定的数组元素，并通过范围进行过滤？
为此，请aggregate()在MongoDB中使用。让我们创建一个包含文档的集合-
> db.demo351.insertOne(
... {
...
... "_id" : "101",
... "ProductDetails" : [
... {
... "ProductName" : "Product-1",
... "ProductPrice" :500
... },
... {
... "ProductName" : "Product-2",
... "ProductPrice" :400
... }
... ]
... }
... );
{ "acknowledged" : true, "insertedId" : "101" }
> db.demo351.insertOne(
... {
...
... "_id" : "102",
... "ProductDetails" : [
... {
... "ProductName" : "Product-3",
... "ProductPrice" :200
... },
... {
... "ProductName" : "Product-4",
... "ProductPrice" :800
... }
... ]
... }
... );
{ "acknowledged" : true, "insertedId" : "102" }在find()方法＆mnus;的帮助下显示集合中的所有文档。
> db.demo351.find();
这将产生以下输出-
{
"_id" : "101", "ProductDetails" : [
{ "ProductName" : "Product-1", "ProductPrice" : 500 },
{ "ProductName" : "Product-2", "ProductPrice" : 400 }
]
}
{
"_id" : "102", "ProductDetails" : [
{ "ProductName" : "Product-3", "ProductPrice" : 200 },
{ "ProductName" : "Product-4", "ProductPrice" : 800 }
]
}以下是查询以查找带有查询的MongoDB文档中的特定数组元素并使用范围过滤-
> db.demo351.aggregate([
... {
... $match: { _id: "102" }
... },
... {
... $addFields: {
... ProductDetails: {
... $filter: {
... input: "$ProductDetails",
... cond: {
... $and: [
... { $gt: [ "$$this.ProductPrice", 600 ] },
... { $lt: [ "$$this.ProductPrice", 900 ] }
... ]
... }
... }
... }
... }
... }
... ])这将产生以下输出-
{ "_id" : "102", "ProductDetails" : [ { "ProductName" : "Product-4", "ProductPrice" : 800 } ] }