# `StreamAgg` Process - Cont'd

![`smart`](STREAMAGG03_aa_003_20231013.png)

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Finally, after scanning all departments, the aggregated results grouped by the `Dept.` column are obtained. The characteristics of the `StreamAgg` operator are as follows:

1. Initial Sorting: The table must be sorted by the grouping column first.
2. Memory Efficiency: It uses only one temporary table, reducing memory usage compared to the `HashAgg` operator.
3. Non-blocking: It can terminate early if only specific groups are needed, avoiding a full table scan.
4. No Parallelism: The `StreamAgg` operator does not support parallel processing.