Documentation Index
Fetch the complete documentation index at: https://docs.prophecy.ai/llms.txt
Use this file to discover all available pages before exploring further.
Overview
The Union gem lets you combine records from different tables for cases such as merging customer databases or aggregating logs from multiple servers.
The gem has a corresponding interactive gem example. See Interactive gem
examples to learn how to run sample pipelines
for this and other gems. | Port | Description |
|---|
| in0 | The first input table. |
| in1 | The second input table. |
| inN | Optional: Additional input tables. |
| out | A single table containing all rows from input tables. |
+ next to Ports.
All input tables must have identical schemas (matching column names and data types). If table columns have different orders or a different number of columns, use the UnionByName gem.
Parameters
| Parameter | Description |
|---|
| Operation Type | Shows that the set operation type is Union |
| Preserve duplicate rows | Checkbox to keep duplicates in the output table |
Example
Let’s say you’re working with two tables: Table A and Table B.
- Both tables contain order-related data.
- Table A contains order information from customer
1, 2, and 3.
- Table B contains order information from customer
1, 2, 3, and 4.
- These tables contain some identical records (duplicates).
Table A
order_id | customer_id | order_date | amount |
|---|
| 101 | 1 | 2024-12-01 | 250.00 |
| 102 | 2 | 2024-12-03 | 150.00 |
| 103 | 1 | 2025-01-15 | 300.00 |
| 104 | 3 | 2025-02-10 | 200.00 |
Table B
order_id | customer_id | order_date | amount |
|---|
| 103 | 1 | 2025-01-15 | 300.00 |
| 104 | 3 | 2025-02-10 | 200.00 |
| 105 | 4 | 2025-03-05 | 400.00 |
| 106 | 2 | 2025-03-07 | 180.00 |
Result without duplicates
The following is the output table without duplicates.
order_id | customer_id | order_date | amount |
|---|
| 101 | 1 | 2024-12-01 | 250.00 |
| 102 | 2 | 2024-12-03 | 150.00 |
| 103 | 1 | 2025-01-15 | 300.00 |
| 104 | 3 | 2025-02-10 | 200.00 |
| 105 | 4 | 2025-03-05 | 400.00 |
| 106 | 2 | 2025-03-07 | 180.00 |
Result with duplicates
The following is the output table when you select Preserve duplicate rows in the gem configuration.
order_id | customer_id | order_date | amount |
|---|
| 101 | 1 | 2024-12-01 | 250.00 |
| 102 | 2 | 2024-12-03 | 150.00 |
| 103 | 1 | 2025-01-15 | 300.00 |
| 104 | 3 | 2025-02-10 | 200.00 |
| 103 | 1 | 2025-01-15 | 300.00 |
| 104 | 3 | 2025-02-10 | 200.00 |
| 105 | 4 | 2025-03-05 | 400.00 |
| 106 | 2 | 2025-03-07 | 180.00 |
Order 103 and 104 are duplicate records.
