Union All

Stack a second table under this one. Twelve monthly files become one dataset.

What it does

Union All adds the rows of another table to the bottom of yours. Join adds columns. Union All adds rows.

Use it for files with the same shape. Monthly exports, one file per branch, or one file per survey wave all fit.

Append a second table

  1. Load the second file first. The picker only lists tables that are already open.
  2. Type union in the Search transforms box, in the Pipeline panel.
  3. Select Union All in the results.
  4. Open the picker under Append rows from. Pick a table.
  5. Set Column matching to By name or By position.
  6. Click Apply.

With nothing else loaded, the panel shows: No other loaded tables available. Load another file to use Union All.

By name or by position

By name is the default. The panel describes it as Columns matched by name; missing columns become NULL.

Column order does not matter in this mode. A column that only one table has becomes empty in the other table's rows.

By position matches the first column to the first column, and so on. The panel describes it as Columns matched left-to-right; counts and types must align.

Pick By position only when the headers differ but the layout is identical.

What By name does with a missing column

March has an extra channel column:

Tableregionsaleschannel
feb_sales rowNorth1200not present
mar_sales rowNorth1450online

The result keeps all three columns:

regionsaleschannel
North1200
North1450online

Files and views both work

The picker lists every other view in the workspace. Each entry names the file and the view.

A view with its own pipeline contributes its finished result, not the raw file.

So you can clean February in its own view, then append that clean output here.

Edit that other view later and this step rebuilds with the new rows.

Tips

  • Append several files with several Union All steps, one per file.
  • Union All keeps duplicates. Add Remove Duplicates after it if you need unique rows.
  • This step adds no source column. Add one in each view with Add Column before you append.
  • By position fails when the column counts differ. Switch to By name in that case.

For SQL users

With By name selected, the step runs as:

SELECT * FROM "feb_sales" UNION ALL BY NAME SELECT * FROM "mar_sales"

By position drops the BY NAME clause.

Try Union All with sample data →

Related Operations

  • Join - Join with another file/table
  • Unnest - Explode delimited column into rows
  • Fill Missing - Fill null values