$eq

Amazon DocumentDB 中的$eq運算子用於比對欄位值等於指定值的文件。此運算子常用於 find()方法，以擷取符合指定條件的文件。

參數

• field ：檢查等式條件的欄位。

• value ：要與 欄位比較的值。

範例 (MongoDB Shell)

下列範例示範 $eq運算子的使用情況，以尋找 name 欄位等於 的所有文件"Thai Curry Palace"。

建立範例文件

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"] }
]);

查詢範例

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

輸出

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

程式碼範例

若要檢視使用 $eq命令的程式碼範例，請選擇您要使用的語言標籤：

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")