$eq

Amazon DocumentDB 中的$eq运算符用于匹配字段值等于指定值的文档。该运算符通常用于检索符合指定条件的文档find()的方法。

参数

• field：要检查相等条件的字段。

• value：要与字段进行比较的值。

示例（MongoDB 外壳）

以下示例演示如何使用$eq运算符来查找该name字段等于的所有文档"Thai Curry Palace"。

创建示例文档

db.restaurants.insertMany([
  { name: "Thai Curry Palace", cuisine: "Thai", features: ["Private Dining"] },
  { name: "Italian Bistro", cuisine: "Italian", features: ["Outdoor Seating"] },
  { name: "Mexican Grill", cuisine: "Mexican", features: ["Takeout"] }
]);

查询示例

db.restaurants.find({ name: { $eq: "Thai Curry Palace" } });

输出

{ "_id" : ObjectId("68ee586f916df9d39f3d9414"), "name" : "Thai Curry Palace", "cuisine" : "Thai", "features" : [ "Private Dining" ] }

代码示例

要查看使用该$eq命令的代码示例，请选择要使用的语言的选项卡：

Node.js

const { MongoClient } = require('mongodb');

async function findByName(name) {
  const client = await MongoClient.connect('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
  const db = client.db('test');
  const collection = db.collection('restaurants');

  const results = await collection.find({ name: { $eq: name } }).toArray();
  console.log(results);

  await client.close();
}

findByName("Thai Curry Palace");

Python

from pymongo import MongoClient

def find_by_name(name):
    client = MongoClient("mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false")
    db = client["test"]
    collection = db["restaurants"]

    results = list(collection.find({ "name": { "$eq": name } }))
    print(results)

    client.close()

find_by_name("Thai Curry Palace")