# Read a file of any format

Acquire / file

one reader that picks the format from the file

Page: <https://meridian.online/operations/read-a-file-of-any-format>

## Status

Runs as a SQL step.

arcform carries it as a `sql:` step today.

## The DuckDB step

the reader is chosen from the file name

It reads the `orders` table the proofs share. Create it first:

```sql
CREATE TABLE orders AS SELECT * FROM (VALUES
  (1,  'Alice Ng',      'north', DATE '2026-01-03', 120.00, 'widget', 'a|b',   '{"channel":"web","items":[1,2]}'),
  (2,  'alice ng',      'north', DATE '2026-01-05',  80.50, 'gadget', 'b',     '{"channel":"shop","items":[3]}'),
  (3,  'Bob  Okafor',   'south', DATE '2026-01-05', 300.00, 'widget', 'a|c',   '{"channel":"web","items":[4,5,6]}'),
  (4,  'Carla Díaz',    'east',  DATE '2026-01-09',  NULL,  'gizmo',  NULL,    '{"channel":"web","items":[]}'),
  (5,  'Bob Okafor',    'south', DATE '2026-01-12',  45.25, 'gadget', 'c',     '{"channel":"phone","items":[7]}'),
  (6,  'Dev Patel',     'west',  DATE '2026-01-12', 510.00, 'widget', 'a',     '{"channel":"web","items":[8,9]}'),
  (7,  'Carla Diaz',    'east',  DATE '2026-01-20',  99.99, 'gizmo',  'b|c',   '{"channel":"shop","items":[10]}'),
  (8,  'Dev Patel',     'west',  DATE '2026-02-02', 510.00, 'widget', 'a',     '{"channel":"web","items":[8,9]}'),
  (9,  'Eve Larsen',    NULL,    DATE '2026-02-03',  15.00, 'gadget', NULL,    '{"channel":"web","items":[11]}'),
  (10, 'Alice Ng',      'north', DATE '2026-02-10', 220.00, 'gizmo',  'a|b|c', '{"channel":"phone","items":[12,13]}')
) t(order_id, customer, region, order_date, amount, product, tags, meta);
```

Then run the statement:

```sql
COPY orders TO '<your_scratch_dir>/auto.parquet'; COPY orders TO '<your_scratch_dir>/auto.csv';
CREATE TEMP TABLE result AS
SELECT (SELECT count(*) FROM '<your_scratch_dir>/auto.parquet') AS from_parquet, (SELECT count(*) FROM '<your_scratch_dir>/auto.csv') AS from_csv;
SELECT * FROM result;
SELECT CASE WHEN ((SELECT from_parquet = 10 AND from_csv = 10 FROM result)) THEN 'as expected' ELSE error('a file read by name alone did not return 10 rows') END AS verdict;
```

Replace `<your_scratch_dir>` with a directory of your own that you can write to before running the statement.

The statement writes `auto.csv` and `auto.parquet` itself, in `<your_scratch_dir>`.

It needs nothing installed beyond DuckDB itself.

## What other tools call it

Meridian's classification; an independent blind rating agreed on 86.2% of 312 rows (exact class, version 2).

- Alteryx Designer: [`Dynamic Input`](https://help.alteryx.com/current/en/designer/tools/developer/dynamic-input-tool.html) (read 2026-09-27)
- Alteryx Designer: [`Input Data`](https://help.alteryx.com/current/en/designer/tools/in-out-tools/input-data-tool.html) (read 2026-09-27)
- Tableau Prep: [`Input`](https://help.tableau.com/current/prep/en-us/prep_configure_dastaset.htm) (read 2026-09-27)