.. _auto_dataset_get_column_values:

*DATASET GET COLUMN VALUES*
===========================

Extracts values from one or more columns of a dataset and returns them as a delimited scalar string. Supports aggregation modes (all, min, max, avg, mode, unique, sum, histogram) so downstream workers can consume column data without loading the full dataset. Use it to inspect, filter, or summarise specific columns within a workflow.

When to use
-----------

Classification: **process**.

Tagged: ``aggregation``, ``avg``, ``column``, ``dataset``, ``delimited``, ``extract``, ``histogram``, ``max``.

Inputs
------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20 20 20

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Dataset
     - dataset_1
     - dataset
     - —
     - 
     - Input dataset whose column values are to be extracted; accepts any tabular dataset object available in the workflow.
   * - Column Names
     - column_names
     - scalar
     - —
     - 
     - One or more column names to extract from the dataset; multiple selections are supported and the list is dynamically populated from dataset_1's headers.
   * - Col Delimiter
     - col_delimiter
     - scalar
     - ,
     - 
     - Character used to separate values belonging to different columns in the output string; defaults to comma (',').
   * - Row Delimiter
     - row_delimiter
     - scalar
     - :
     - 
     - Character used to separate individual row values within a single column in the output string; defaults to colon (':').
   * - Type Of Value To Return
     - type_of_value_to_return
     - scalar
     - all
     - 
     - Aggregation mode applied before returning values: 'all' returns every row value, while 'min', 'max', 'avg', 'mode', 'sum', 'unique', and 'histogram' return the corresponding statistic; defaults to 'all'.

Outputs
-------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20

   * - Label
     - ID
     - Type
     - Description
   * - Column Values
     - column_values
     - scalar
     - Delimited scalar string containing the extracted (and optionally aggregated) column values, with columns separated by col_delimiter and rows separated by row_delimiter; unique values are deduplicated when reduce_type is 'unique'.

Disciplines
-----------

- data.dataset.transform
- data.statistics

Runnable example
----------------

A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: `/api/workflow/example?id=dataset_get_column_values <https://www.d3view.com/api/workflow/example?id=dataset_get_column_values>`_

.. raw:: html

   <hr style="margin-top:2em">
   <p style="font-size:11px;color:#888">
   Auto-generated from <code>transformation</code> schema. Worker id: <code>dataset_get_column_values</code>. Schema hash: <code>bc60d9bf6537</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>