Writing Something

SELECT first_name,
  last_name,
  salary
FROM employees
WHERE salary >
  (SELECT salary
   FROM employees
   WHERE last_name = 'Abel')
;
 
 
SELECT first_name,
  last_name,
  salary
FROM employees
WHERE salary < ANY
  (SELECT salary
   FROM employees
   WHERE job_id = 'IT_PROG')
AND job_id <> 'IT_PROG';
 
 
SELECT first_name,
  last_name,
  salary
FROM employees
WHERE salary <
  (SELECT MAX(salary)
   FROM employees
   WHERE job_id = 'IT_PROG')
AND job_id <> 'IT_PROG';
 
 
SELECT first_name,
  last_name,
  salary
FROM employees
WHERE salary < ALL
  (SELECT salary
   FROM employees
   WHERE job_id = 'IT_PROG')
AND job_id <> 'IT_PROG';
 
 
SELECT first_name,
  last_name,
  salary
FROM employees
WHERE salary <
  (SELECT MIN(salary)
   FROM employees
   WHERE job_id = 'IT_PROG')
AND job_id <> 'IT_PROG';
 
 
SELECT employee_id,
  department_id
FROM job_history
WHERE employee_id = 200
UNION ALL
SELECT employee_id,
  department_id
FROM employees
WHERE employee_id = 200;
 
 
SELECT employee_id,
  department_id
FROM job_history INTERSECT
SELECT employee_id,
  department_id
FROM employees;
 
 
SELECT employee_id
FROM employees minus
SELECT employee_id
FROM job_history;
 
 
SELECT employee_id,
  department_id
FROM job_history
WHERE employee_id = 200
UNION ALL
SELECT employee_id,
  department_id
FROM employees
WHERE employee_id = 200;
 
 
SELECT employee_id,
  department_id
FROM job_history INTERSECT
SELECT employee_id,
  department_id
FROM employees;
 
 
SELECT employee_id
FROM employees minus
SELECT employee_id
FROM job_history;
 
 
SELECT location_id,
  department_name "department",
  to_char(NULL) "warehouse location"
FROM departments
UNION
SELECT location_id,
  to_char(NULL) "department",
  state_province "warehouse location"
FROM locations;
 
 
SELECT employee_id,
  job_id,
  salary,
  hire_date
FROM employees
UNION
SELECT employee_id,
  job_id,
  0,
  sysdate
FROM job_history;
 
 
SELECT department_id
FROM departments INTERSECT
SELECT department_id
FROM employees
WHERE job_id <>('ST_CLERK');
 
 
SELECT country_id,
  country_name
FROM countries minus
SELECT DISTINCT x.country_id,
  x.country_name
FROM locations l,
  countries x
WHERE l.country_id = x.country_id
 AND l.location_id IN
  (SELECT DISTINCT location_id
   FROM departments)
;
 
 
--insert tabloyu kilitler! update, delete satırı kilitler.
INSERT
INTO departments(department_id,   department_name,   manager_id,   location_id)
VALUES(280,   'Serdar',   100,   1700);
 
 
 
INSERT
INTO departments(department_id,   department_name)
VALUES(290,   'Serdar 2' );
 
 
ROLLBACK;
 
 
 
CREATE TABLE emp2 AS
SELECT *
FROM employees;
 
commit;
 
INSERT
INTO emp2
SELECT *
FROM emp2;
 
 
INSERT
INTO emp2(last_name,      salary,      email,      hire_date,      job_id)
SELECT last_name,
     salary,
     email,
     hire_date,
     job_id
FROM emp2;
 
 
UPDATE emp2
SET salary = 24000
WHERE employee_id = 100;
 
 
UPDATE emp2
SET department_id =
     (SELECT department_id
      FROM employees
      WHERE employee_id = 100)
WHERE job_id = 'AD_ASST';
 
 
DELETE FROM emp2
WHERE employee_id = 101;
 
 
TRUNCATE TABLE emp2;