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The Alteryx Append Fields tool attaches every row from one dataset to every row of another. Prophecy implements equivalent behavior using the Join gem.

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Automated migration results

When Import encounters an Alteryx Append tool, it recreates the behavior using a Join gem. Although the Alteryx Append tool behaves like a Cartesian join, Import does not emit a literal CROSS JOIN. Instead, it generates SQL that attaches the selected fields from the secondary input to each row of the primary input using a controlled join pattern. This approach avoids optimizer restrictions associated with explicit CROSS JOIN, preserves field-selection semantics, and ensures consistent behavior.
  • Prophecy generates a Join gem that combines the target and source streams.
  • The Join is configured with a constant condition (1 = 1), effectively performing a cross join between the two inputs.
  • All columns from both inputs are preserved (in0.* and in1.*), so each record from one stream is replicated for every record in the other stream, matching Alteryx Append semantics.
  • The resulting dataset is then available as a single downstream output in the Prophecy pipeline.

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Manually replicate in Prophecy

  1. Add a Join gem configured as a Cross Join.
  2. Connect two datasets to the Join gem.
  3. Preview results in the Data Explorer.

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Configuration options

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Alteryx Append Fields tool

  • Attach the Target and Source streams to the Append Fields tool.
  • Optionally, deselect any Source fields you do not want replicated onto each Target row.

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Prophecy Join gem

Attach two datasets to a Join gem configured as a Cross Join.

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Output behavior

Alteryx produces a dataset where all combination pairs (Cartesian) or matched rows (key-based) are appended. Prophecy outputs combined rows that match Alteryx’s logical intent.

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Known caveats

  • Target and Source ports do not appear in Prophecy.
  • Prophecy often imports cross-joins as joins on a constant condition (such as 1 = 1). This is an explicit representation of a cross join, and is used to preserve semantics and lineage while stabilizing planner behavior. The resulting data is identical to Alteryx’s no-key join or append behavior.
  • Cross joins can grow extremely large; ensure datasets are appropriately sized.

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Example

Goal: Add a simple product_category dataset to every record in a daily_ production log.

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Alteryx Append tool example

  1. Add an Append tool to the canvas.
  2. Connect the daily_production dataset to the T (target) anchor.
  3. Connect the product_category dataset to the S (source) anchor.

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Prophecy example

In Prophecy, this operation is represented using a Join-based pattern that adds the selected fields from the secondary dataset to each row of the primary dataset. To reproduce this manually in Prophecy:
  1. Add a Join gem configured as a Cross Join.
  2. Connect the daily_production and product_category datasets to the Join gem.
The output contains all rows from the primary dataset with the selected source fields appended.