> For the complete documentation index, see [llms.txt](https://docs-v3.toucantoco.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-v3.toucantoco.com/data-management-in-datahub/datasets-in-toucan/preparing-data/overview-of-youprep-tm/aggregate/hierarchical-rollup.md).

# Hierarchical rollup

The Hierarchical rollup step allows you to compute aggregated data at every level of a hierarchy, specified as a series of columns from top to bottom level. The output data structure stacks the data of every level of the hierarchy, specifying for every row the label, level and parent in dedicated columns.

Aggregated rows can be computed with using either `sum`, `average`, `count`, `count distinct`, `min`, `max`, `first` or `last`.

### Step parameters

* `Hierarchal columns (from top to bottom level)`: here you must specify the list of columns that have a hierarchical link, in hierarchical order from top to bottom level.
* `(Optional) Columns to aggregate`: Here you can specify one or more columns to aggregate, with the corresponding aggregation function to be applied. You can add a column to aggregate by clicking on the button `Add aggregation`.
  * `Columns`: the columns to be aggregated (you can apply the same aggregation function to several columns at once)
  * `Function` the aggregation function to be applied (`sum`, `average`, `count`, `count distinct`, `min`, `max`, `first` or `last`).
* `(Optional) Group rollup by`: Optional, if you need to apply the rollup computation by groups of rows, you may specify here columns used to constitute groups.
* `(Optional) Label column name to be created`: Optional, if you want to give a custom name to the output labels column (`label` by default).
* `(Optional) Level column name to be created`: Optional, if you want to give a custom name to the output levels column (`level` by default).
* `(Optional) Parent column name to be created`: Optional, if you want to give a custom name to the output parents column (`parent` by default).

### Example

**Input**

<figure><img src="/files/S5nkjyQNr5f3GLEG8Psz" alt=""><figcaption><p>Aggregate - hierarchical rollup input</p></figcaption></figure>

**Configuration**

```json
{
    "hierarchy": ["continent", "country", "city"],
    "aggregations": [
        {
            "aggfunction": "sum",
            "columns": ["value", "value_bis"]
        }        
    ],
    "group_by": [],
    "label_col": "label",
    "level_col": "level",
    "parent_label_col": "parent"
}
```

**Result**

<figure><img src="/files/zRM21iCmIsCioqOn2E7S" alt=""><figcaption><p>Aggregate - hierarchical rollup output</p></figcaption></figure>


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