### Discussed in https://github.com/apache/airflow/discussions/33345

<div type='discussions-op-text'>

<sup>Originally posted by **vuphamcs** August 11, 2023</sup>
### Description

Is there a variable similar to `prev_start_date_success` but for the previous DAG run’s completion date? The value I’m hoping to retrieve to use within the next DAG run is `2023-08-10 16:04:30`

![image](https://github.com/apache/airflow/assets/1600760/9e2af349-4c3e-47e1-8a1a-9d8827b56f57)


### Use case/motivation

One particular use case is to help guarantee that the next DAG run only queries data that was inserted during the existing DAG run, and not the past DAG run.

```python
prev_ts = context['prev_end_date_success']

sql = f"SELECT * FROM results WHERE created_at > {context['prev_end_date_success']}"
```

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)
</div>
self.start_date = start_date
        self.end_date = end_date
        self.try_number = try_number
        self.state = state
        self.executor_config = executor_config
        self.run_as_user = run_as_user
        self.pool = pool
        self.priority_weight = priority_weight
        self.queue = queue
        self.key = key
    def __eq__(self, other):
        if isinstance(other, self.__class__):
            return self.__dict__ == other.__dict__
        return NotImplemented
    def as_dict(self):
        warnings.warn(
            "This method is deprecated. Use BaseSerialization.serialize.",
            RemovedInAirflow3Warning,
            stacklevel=2,
        )
        new_dict = dict(self.__dict__)
        for key in new_dict:
            if key in ["start_date", "end_date"]:
                val = new_dict[key]
                if not val or isinstance(val, str):
                    continue
                new_dict.update({key: val.isoformat()})
        return new_dict
    @classmethod
    def from_ti(cls, ti: TaskInstance) -> SimpleTaskInstance: