.. _auto_dataset_join_row:

*JOIN A ROW TO ALL ROWS OF THE DESTINATION DATASET*
===================================================

Joins a single row from a source dataset as new columns onto every row of a destination dataset. The specific source row is selected by index (default: first row), and only the chosen columns are appended. Use this worker to broadcast scalar metadata or a lookup row across an entire tabular dataset.

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

Classification: **process**.

Tagged: ``broadcast``, ``column_append``, ``dataset_merge``, ``join``, ``row_join``, ``tabular``.

Inputs
------

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

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Source
     - source_dataset
     - dataset
     - —
     - 
     - Dataset containing the row whose values will be broadcast onto the destination; if multiple rows are present, the row selected by source_row_index is used (defaults to the first row).
   * - Destination Dataset
     - dest_dataset
     - dataset
     - —
     - 
     - Destination dataset whose every row will be augmented with the selected columns from the source row; all existing rows are preserved.
   * - Source Columns
     - source_column
     - scalar
     - —
     - 
     - One or more column names from source_dataset to append to the destination; leave empty to include all source columns.
   * - Source Dataset Index
     - source_row_index
     - scalar
     - 0
     - 
     - Zero-based integer index of the row to select from source_dataset (default: 0, i.e. the first row); increase this to broadcast a different source row.

Outputs
-------

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

   * - Label
     - ID
     - Type
     - Description
   * - dataset_join_row_output_1
     - dataset_join_row_output_1
     - dataset
     - Resulting dataset containing all rows from dest_dataset with the selected source columns appended as additional columns, each populated with the values from the chosen source row.

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_join_row <https://www.d3view.com/api/workflow/example?id=dataset_join_row>`_

.. 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_join_row</code>. Schema hash: <code>db7437ffeecf</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>