"Column check constraint cannot reference other columns"
Your syntax is not correct for row level CHECK constraints.


  CHECK (DELY_DATE &gt; S_ORDER_DATE) needs to be at the table level.
  
  -- from Martin Smith's comments


Within the CREATE TABLE statement:

CREATE TABLE SALES_ORDER
(
   S_ORDER_NO   VARCHAR2(6) PRIMARY KEY CHECK (S_ORDER_NO LIKE 'O'),
   S_ORDER_DATE DATE,
   DELY_ADDR    VARCHAR2(25),
   SALESMAN_NO  VARCHAR2(6) REFERENCES SALESMAN_MASTER(SALESMAN_NO),
   DELY_TYPE    CHAR(1) DEFAULT 'F' CHECK (DELY_TYPE IN ('P', 'F')),
   BILLED_YN    CHAR(1),
   DELY_DATE    DATE,
   ORDER_STATUS VARCHAR2(10) CHECK (ORDER_STATUS IN ('PROCESS', 'FULFILLED', 'BLOCKORDER', 'CANCELED')),
   constraint &lt;CNAME&gt; CHECK (DELY_DATE &gt; S_ORDER_DATE)
); 


Outside of the CREATE TABLE statement:

CREATE TABLE SALES_ORDER
(
   S_ORDER_NO   VARCHAR2(6) PRIMARY KEY CHECK (S_ORDER_NO LIKE 'O'),
   S_ORDER_DATE DATE,
   DELY_ADDR    VARCHAR2(25),
   SALESMAN_NO  VARCHAR2(6) REFERENCES SALESMAN_MASTER(SALESMAN_NO),
   DELY_TYPE    CHAR(1) DEFAULT 'F' CHECK (DELY_TYPE IN ('P', 'F')),
   BILLED_YN    CHAR(1),
   DELY_DATE    DATE,
   ORDER_STATUS VARCHAR2(10) CHECK (ORDER_STATUS IN ('PROCESS', 'FULFILLED', 'BLOCKORDER', 'CANCELED'))
);


-- from Lennart's comments
ALTER TABLE SALES_ORDER ADD CONSTRAINT &lt;CNAME&gt; CHECK (DELY_DATE &gt; S_ORDER_DATE);