09. Union: combine branch data

Combine two sales datasets into one table by column names, even when their order differs.

Task and prerequisites

Combine two sales datasets into one table by column names, even when their order differs.

This example uses demonstration data and settings. Validate the expected result in your own environment before connecting production destinations. Identifiers demo_* are illustrative: select your own training connections or sources in the editor. The JSON below shows the block and connection structure, not a ready-to-transfer flow archive.

Training input data

north.csv

Branch;Amount
North;100
North;40

south.csv

Amount;Branch
80;South

Blocks, connections and exact settings

09. Union: combine branch data. Example 09 topology: 4 blocks, 3 connections. Node identifiers and ports from the configured graph are preserved. — **Flow diagram 09**
Example 09 topology: 4 blocks, 3 connections. Node identifiers and ports from the configured graph are preserved.

Add the listed blocks in the designer, open each block's properties and set these values. Names demo_* identify training sources and connections.

Block	Setting
1 File `north`	Role: `source` Source: `demo_north` Read settings: Sheet: `CSV` Range: `A1:B3` First row is the header: `так` Delimiter: `;`
2 File `south`	Role: `source` Source: `demo_south` Read settings: Sheet: `CSV` Range: `A1:B2` First row is the header: `так` Delimiter: `;`
3 Union `union`	Inputs: Identifier: `north` Label: `Північ` Identifier: `south` Label: `Південь` Mode: `by_name`
4 Data export `out`	Format: `csv` File name: `all_branches` Purpose: `download` Delimiter: `;` Time zone: `Europe/Kyiv`

Port connections

north out → union north
south out → union south
union out → out in

Complete graph configuration as JSON

{
  "version": 3,
  "nodes": [
    {
      "id": "north",
      "type": "file",
      "label": "north",
      "config": {
        "role": "source",
        "source_id": "demo_north",
        "options": {
          "sheet": "CSV",
          "range": "A1:B3",
          "header": true,
          "delimiter": ";"
        }
      }
    },
    {
      "id": "south",
      "type": "file",
      "label": "south",
      "config": {
        "role": "source",
        "source_id": "demo_south",
        "options": {
          "sheet": "CSV",
          "range": "A1:B2",
          "header": true,
          "delimiter": ";"
        }
      }
    },
    {
      "id": "union",
      "type": "union",
      "label": "union",
      "config": {
        "inputs": [
          {
            "id": "north",
            "label": "Північ"
          },
          {
            "id": "south",
            "label": "Південь"
          }
        ],
        "mode": "by_name"
      }
    },
    {
      "id": "out",
      "type": "export",
      "label": "out",
      "config": {
        "format": "csv",
        "filename": "all_branches",
        "destination": "download",
        "delimiter": ";",
        "timezone": "Europe/Kyiv"
      }
    }
  ],
  "edges": [
    {
      "source": "north",
      "target": "union",
      "source_port": "out",
      "target_port": "north"
    },
    {
      "source": "south",
      "target": "union",
      "source_port": "out",
      "target_port": "south"
    },
    {
      "source": "union",
      "target": "out",
      "source_port": "out",
      "target_port": "in"
    }
  ]
}

Expected result

Branch	Amount
North	100
North	40
South	80

Union appends rows; it does not sum Amount or remove duplicates. The result is 3 rows with a total amount of 220.

Run and verify

Upload the files with differing column orders without manually rearranging them.
Choose by_name in Union and two separate inputs, north/south.
Check that South appears in Branch and 80 in Amount.

Common errors

mode=position matches positions and would swap the meanings of the columns in this dataset.
Branch and branch are different names; align names with mapping first.
If totals are required, add Group after Union; Union does not create them itself.