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# $tsSecond
<a name="tsSecond"></a>

8.0.1 版中的新增内容。

Amazon DocumentDB 中的`$tsSecond`运算符将时间戳值的秒部分作为长整数（Unix 纪元秒）返回。

**参数**
+ `expression`：解析为时间戳的表达式。

## 示例（MongoDB Shell）
<a name="tsSecond-examples"></a>

以下示例说明如何使用`$tsSecond`运算符从时间戳值中提取秒数部分。

**创建示例文档 **

```
db.events.insertMany([
  {_id: 1, ts: Timestamp(1678900000, 1)},
  {_id: 2, ts: Timestamp(1678900000, 2)},
  {_id: 3, ts: Timestamp(1678900001, 1)}
]);
```

**查询示例 **

```
db.events.aggregate([
  { $project: { seconds: { $tsSecond: "$ts" } } }
]);
```

**输出**

```
[
  {_id: 1, seconds: Long("1678900000")},
  {_id: 2, seconds: Long("1678900000")},
  {_id: 3, seconds: Long("1678900001")}
]
```

## 代码示例
<a name="tsSecond-code"></a>

要查看使用`$tsSecond`运算符的代码示例，请选择要使用的语言的选项卡：

------
#### [ Node.js ]

```
const { MongoClient, Timestamp } = require('mongodb');

async function example() {
  const client = new MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false');
  try {
    await client.connect();
    const db = client.db('test');
    const collection = db.collection('events');
    const result = await collection.aggregate([
      { $project: { seconds: { $tsSecond: "$ts" } } }
    ]).toArray();
    console.log(result);
  } finally {
    await client.close();
  }
}
example();
```

------
#### [ Python ]

```
from pymongo import MongoClient

def example():
    client = MongoClient('mongodb://<username>:<password>@<cluster-endpoint>:27017/?tls=true&tlsCAFile=global-bundle.pem&replicaSet=rs0&readPreference=secondaryPreferred&retryWrites=false')
    try:
        db = client['test']
        collection = db['events']
        result = list(collection.aggregate([
            {'$project': {'seconds': {'$tsSecond': '$ts'}}}
        ]))
        print(result)
    finally:
        client.close()

example()
```

------