DELETE FROM accounts
WHERE id NOT IN (SELECT p.account_id
FROM players p)
DELETE FROM accounts
WHERE NOT EXISTS(SELECT NULL
FROM players p
WHERE p.account_id = id)
bring back all accountsYes its possible with single query.
Try this (not tested), so maybe try this on test database, but should work.
Code:DELETE FROM accounts WHERE NOT EXISTS(SELECT NULL FROM players p WHERE p.account_id = id)
DELETE FROM accounts
WHERE id NOT IN (SELECT p.account_id
FROM players p)