Oracle 21c

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CREATE TABLE sales (
  payment   NVARCHAR2(32),
  amount    FLOAT,
  CONSTRAINT cash_limit check ((payment <> 'CASH') OR (amount <= 500))
);
INSERT INTO sales VALUES ('CARD', 1000)
1 rows affected

INSERT INTO sales VALUES ('CASH', 1000)
ORA-02290: check constraint (FIDDLE_RRTEUUCBYHAGJHVCUHPJ.CASH_LIMIT) violated

INSERT INTO sales VALUES ('CASH', 500)
1 rows affected