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$dateSubtract
5.0 版的新功能
Amazon DocumentDB $dateSubtract 中的彙總運算子可讓您從日期值中減去指定的持續時間。
參數
範例 (MongoDB Shell)
下列範例示範如何使用 $dateSubtract運算子來計算一年前從目前日期起算的日期。
建立範例文件
db.events.insertOne({
eventName: "Player joined",
eventTime: ISODate("2023-04-01T12:00:00Z")
});
查詢範例
db.events.aggregate([
{
$project: {
eventName: 1,
oneYearAgo: {
$dateSubtract: {
startDate: "$eventTime",
amount: 1,
unit: "year"
}
}
}
}
])
輸出
{
"_id" : ObjectId("64567890abcdef012345678"),
"eventName" : "Player joined",
"oneYearAgo" : ISODate("2022-04-01T12:00:00Z")
}
程式碼範例
若要檢視使用 $dateSubtract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 example() {
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 events = db.collection('events');
const result = await events.aggregate([
{
$project: {
eventName: 1,
oneYearAgo: {
$dateSubtract: {
startDate: "$eventTime",
amount: 1,
unit: "year"
}
}
}
}
]).toArray();
console.log(result);
await client.close();
}
example();
- Python
-
from pymongo import MongoClient
from bson.date_time import datetime
def example():
client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
db = client['test']
events = db['events']
result = list(events.aggregate([
{
'$project': {
'eventName': 1,
'oneYearAgo': {
'$dateSubtract': {
'startDate': '$eventTime',
'amount': 1,
'unit': 'year'
}
}
}
}
]))
print(result)
client.close()
example()
