# Search text by relevance

Model / text

full-text search ranked by relevance

Page: <https://meridian.online/operations/search-text-by-relevance>

## Status

Runs as a SQL step.

arcform carries it as a `sql:` step today, with the `fts` extension.

## The DuckDB step

full-text search ranked by BM25

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
INSTALL fts; LOAD fts;
CREATE TABLE docs AS SELECT order_id, customer || ' ordered a ' || product || ' in the ' || coalesce(region, 'unknown') || ' region' AS body FROM orders;
PRAGMA create_fts_index('docs', 'order_id', 'body');
CREATE TEMP TABLE result AS
SELECT * FROM (SELECT order_id, body, fts_main_docs.match_bm25(order_id, 'widget north') AS score FROM docs) WHERE score IS NOT NULL;
SELECT order_id, body, round(score, 4) AS score FROM result ORDER BY score DESC LIMIT 3;
SELECT CASE WHEN ((SELECT arg_max(order_id, score) = 1 AND count(*) FILTER (WHERE body NOT LIKE '%widget%' AND body NOT LIKE '%north%') = 0 FROM result)) THEN 'as expected' ELSE error('the order that is both a widget and in the north did not rank first') END AS verdict;
```

It needs the `fts` extension.

## What other tools call it

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

- Duckle: [`Full-Text Search`](https://github.com/slothflowlabs/duckle/blob/f85f8960edfb6efbf4cb89d58a7b32e16df0e867/website/docs/components.html) (read 2026-09-25)
- KNIME Analytics Platform: [`KNIME Indexing and Searching (extension)`](https://api.hub.knime.com/extensions/org.knime.features.ext.lucene) (read 2026-09-27)
- subtoken: [`match_bm25`](https://duckdb.org/docs/current/core_extensions/full_text_search.html) (read 2026-09-27)