CREATE TABLE employed(
  empid NUMBER,
  empname VARCHAR2(10),
  dept VARCHAR2(10),
  salary NUMBER
);

CREATE TABLE sal_log (
  log_id NUMBER GENERATED ALWAYS AS IDENTITY,
  empid NUMBER,
  empname VARCHAR2(10),
  old_salary NUMBER,
  new_salary NUMBER,
  update_date DATE
);

-- Insert the values in the employee table
insert into employed values(1,'Dinesh','IT',1000000);
insert into employed values(2,'sanjay','SALES',500000);

-- Create the trigger
CREATE OR REPLACE TRIGGER log_sal_update
BEFORE UPDATE ON employed
FOR EACH ROW
BEGIN
  IF :OLD.salary != :NEW.salary THEN
    INSERT INTO sal_log (empid, empname, old_salary, new_salary, update_date)
    VALUES (:OLD.empid, :OLD.empname, :OLD.salary, :NEW.salary, SYSDATE);
  END IF;
END;
/
-- Insert the values in the employee table
insert into employed values(1,'Dinesh','IT',1000000);
insert into employed values(2,'sanjay','SALES',500000);

-- Update the salary of an employee
UPDATE employed
SET salary = 60000
WHERE empid = 1;
-- Display the employee table
SELECT * FROM employed;

-- Display the salary_log table
SELECT * FROM sal_log;