# Compare and combine conditions

Shape / columns

comparison and boolean expressions

Page: <https://meridian.online/operations/compare-and-combine-conditions>

## Status

Runs as a SQL step.

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

## The DuckDB step

comparison and boolean expressions

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
CREATE TEMP TABLE result AS
SELECT order_id, amount BETWEEN 50 AND 250 AS mid, region IN ('north', 'south') AND NOT (product = 'gizmo') AS core_line,
       region IS DISTINCT FROM 'west' AS not_west FROM orders;
SELECT * FROM result;
SELECT CASE WHEN ((SELECT count(*) FILTER (WHERE mid) = 4 AND count(*) FILTER (WHERE core_line) = 4 AND count(*) FILTER (WHERE not_west) = 8 AND count(*) FILTER (WHERE mid IS NULL) = 1 FROM result)) THEN 'as expected' ELSE error('a comparison counted the wrong rows, or the null amount did not stay null') END AS verdict;
```

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).

- Ibis: [`And`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`Between`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`Equals`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`Greater`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`GreaterEqual`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`IdenticalTo`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`InValues`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`Less`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`LessEqual`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`Not`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`NotEquals`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`Or`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- Ibis: [`Xor`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/logical.py) (read 2026-09-27)
- OpenRefine: [`Boolean functions`](https://openrefine.org/docs/manual/grelfunctions#boolean-functions) (read 2026-09-27)
- Polars: [`Expr boolean expressions (group)`](https://docs.pola.rs/api/python/stable/reference/expressions/boolean.html) (read 2026-09-27)
- Polars: [`Expr operators: binary (group)`](https://docs.pola.rs/api/python/stable/reference/expressions/operators.html) (read 2026-09-27)
- Polars: [`Expr operators: comparison (group)`](https://docs.pola.rs/api/python/stable/reference/expressions/operators.html) (read 2026-09-27)
- Polars: [`Expr operators: conjunction (group)`](https://docs.pola.rs/api/python/stable/reference/expressions/operators.html) (read 2026-09-27)
- Polars: [`SQL operators (group)`](https://docs.pola.rs/api/python/stable/reference/sql/operators/index.html) (read 2026-09-27)