Find Rows That Violate A Data Rule

Use a `WHERE` predicate to list rows that already break a business or constraint rule.

Created May 10, 2026 Last updated May 10, 2026 5/5 supported engines validation-green 1 example 2 scenarios

Docker-validated Not currently validation-green

Example 1

Find inventory rows with invalid negative values

The intended rule is that quantity and price cannot be negative. Row 2 violates the quantity rule, and row 3 violates the price rule. Rows 1 and 4 already satisfy both checks, so they are not returned.

Source table data Rows loaded before the example query runs.

Setup

CREATE TABLE inventory (id INT, item VARCHAR(50), quantity INT, price INT);

INSERT INTO
  inventory
VALUES
  (1, 'Widget', 12, 25),
  (2, 'Gadget', -3, 10),
  (3, 'Cable', 5, -1),
  (4, 'Bracket', 0, 8);

Validated query Shared across supported engines.

SQL

SELECT
  id,
  item,
  quantity,
  price
FROM
  inventory
WHERE
  quantity < 0
  OR price < 0
ORDER BY
  id;

Expected result Returned rows for the shared example.

id	item	quantity	price
2	Gadget	-3	10
3	Cable	5	-1

The rule is a simple predicate, so the same audit SQL and result work across supported engines.

Useful when

Where this command helps.

finding negative quantities or prices before adding check constraints
validating staged data before loading it into production tables

Explanation

What the command is doing.

Before adding a CHECK constraint or promoting imported data, audit the existing rows with the same rule expressed as a WHERE filter. The query should return only the rows that need investigation or cleanup. This is different from creating the constraint: it is a read-only preflight check that tells you whether existing data is clean enough for the rule to be enforced.

Find Rows That Violate A Data Rule

Find inventory rows with invalid negative values

Where this command helps.

What the command is doing.

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