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mongodb - 带有嵌套对象数组的猫鼬查找查询

问题描述

我有一个用户数据集合，其中包含一个包含对象嵌套数组的朋友列表。

{username: "abcd", friends: [{name: "A", status : "active", code: "X1"},{name: "B", status : "inactive", code: "X2"}, {name: "B", status : "active", code: "X3"}]}
{username: "xyz", friends: [{name: "A", status : "active", code: "X1"},{name: "E", status : "inactive", code: "X2"}, {name: "F", status : "active", code: "X3"}]}
{username: "xyz", friends: [{name: "X", status : "active", code: "X1"},{name: "E", status : "inactive", code: "X2"}, {name: "F", status : "active", code: "X3"}]}

我正在尝试查找谁有朋友名字是“A”的查询。我得到了两条包含所有数据的记录。
我尝试使用以下查询。

users.find({"friends.name" : "A"});

电流输出：

{username: "abcd", friends: [{name: "A", status : "active", code: "X1"},{name: "B", status : "inactive", code: "X2"}, {name: "B", status : "active", code: "X3"}]}
{username: "xyz", friends: [{name: "A", status : "active", code: "X1"},{name: "E", status : "inactive", code: "X2"}, {name: "F", status : "active", code: "X3"}]}

预期输出：

{username: "abcd", friends: [{name: "A", status : "active", code: "X1"}]}
{username: "xyz", friends: [{name: "A", status : "active", code: "X1"}]}

结果应仅返回名称为“A”的人。其他对象数据不应返回。

你能帮助建立像上面输出的查询吗？

标签： mongodbmongoose

解决方案

你可以projection这样使用：

db.collection.find({
  "friends.name": "A"
},
{
  "username": 1,
  "friends.$": 1
})

这里的例子

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