.. _auto_dataset_combine_column:

*COMBINE DATASETS BASED ON PRIMARY KEYS*
========================================

Merges two datasets by joining on one or more primary-key columns and appending a specified column from Dataset2 into Dataset1. Use this worker when you need to enrich a dataset with an additional column sourced from a second dataset that shares common key columns.

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

Classification: **process**.

Tagged: ``column_append``, ``combine``, ``dataset``, ``join``, ``merge``, ``primary_key``, ``process``.

Inputs
------

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

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Dataset1
     - dataset1
     - dataset
     - —
     - 
     - The base dataset (tabular) into which the new column will be merged; must contain the primary-key column(s) specified in 'primarykeys'.
   * - Dataset2
     - dataset2
     - dataset
     - Unknown
     - 
     - The secondary dataset (tabular) supplying the column to be combined; must share the same primary-key column(s) with Dataset1.
   * - Primary Keys
     - primarykeys
     - scalar
     - —
     - 
     - Comma-separated list of column name(s) used as join keys to match rows between Dataset1 and Dataset2 (e.g., 'id' or 'id,timestamp').
   * - Column To Combine
     - columntocombine
     - scalar
     - —
     - 
     - Name of the single column in Dataset2 that will be appended to Dataset1 after the key-based join (e.g., 'temperature').

Outputs
-------

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

   * - Label
     - ID
     - Type
     - Description
   * - dataset_combine_column_output_1
     - dataset_combine_column_output_1
     - dataset
     - The enriched dataset containing all columns from Dataset1 plus the requested column from Dataset2, aligned on the specified primary keys.

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

- data.dataset.transform

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

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

.. 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_combine_column</code>. Schema hash: <code>8e5dddb8a588</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>