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WITH users AS (
SELECT '123456' AS id UNION ALL
SELECT '532614' UNION ALL
SELECT '549481' UNION ALL
SELECT '832482'
),
houses AS (
SELECT 1 AS id, '123456' AS user_one, '532614' AS user_two UNION ALL
SELECT 2, '549481', '123456' UNION ALL
SELECT 3, '532614', '123456' UNION ALL
SELECT 4, '549481', '532614'
)
SELECT u.id
FROM users u
WHERE NOT EXISTS (SELECT 1 FROM houses h
WHERE h.user_one = '123456' AND h.user_two = u.id) AND
u.id <> '123456';
| id |
|---|
| 549481 |
| 832482 |