Answer: Append

The default output mode for such queries is **Append**. This mode ensures that only new rows added to the Result Table since the last trigger are outputted to the sink. It's specifically designed for scenarios where the existing rows in the Result Table do not change, guaranteeing each row is output exactly once, assuming the sink is fault-tolerant. This mode is compatible with queries involving operations like `select`, `where`, `map`, `flatMap`, `filter`, and `join`. Other modes like **Complete** and **Update** serve different purposes, such as outputting the entire Result Table or only the updated rows, respectively.

Author: LeetQuiz Editorial Team