SQL. مسلية الألغاز

SELECT * FROM employees 

 SELECT * FROM employees WHERE first_name = 'David'; 

 SELECT * FROM employees WHERE job_id = 'IT_PROG' 

 SELECT * FROM employees WHERE department_id = 50 AND salary > 4000; 

 SELECT * FROM employees WHERE department_id = 20 OR department_id = 30; 

 SELECT * FROM employees WHERE first_name LIKE '%a'; 

 SELECT * FROM employees WHERE (department_id = 50 OR department_id = 80) AND commission_pct IS NOT NULL; 

 SELECT * FROM employees WHERE first_name LIKE '%n%n%'; 

 SELECT * FROM employees WHERE first_name LIKE '%_____%'; 

 SELECT * FROM employees WHERE salary BETWEEN 8000 AND 9000; 

 SELECT * FROM employees WHERE first_name LIKE '%\%%' ESCAPE '\'; 

 SELECT DISTINCT manager_id FROM employees WHERE manager_id IS NOT NULL; 

 SELECT first_name || '(' || LOWER (job_id) || ')' employee FROM employees; 

 SELECT * FROM employees WHERE LENGTH (first_name) > 10; 

 SELECT * FROM employees WHERE INSTR (LOWER (first_name), 'b') > 0; 

 SELECT * FROM employees WHERE INSTR (LOWER (first_name),'a',1,2) > 0; 

 SELECT * FROM employees WHERE MOD (salary, 1000) = 0; 

 SELECT phone_number, SUBSTR (phone_number, 1, 3) new_phone_number FROM employees WHERE phone_number LIKE '___.___.____'; 

 SELECT department_name, SUBSTR (department_name, 1, INSTR (department_name, ' ')-1) first_word FROM departments WHERE INSTR (department_name, ' ') > 0; 

 SELECT first_name, SUBSTR (first_name, 2, LENGTH (first_name) - 2) new_name FROM employees; 

 SELECT * FROM employees WHERE SUBSTR (first_name, -1) = 'm' AND LENGTH(first_name)>5; 

 SELECT NEXT_DAY (SYSDATE, 'FRIDAY') next_friday FROM DUAL; 

 SELECT * FROM employees WHERE MONTHS_BETWEEN (SYSDATE, hire_date) / 12 > 17; 

 SELECT * FROM employees WHERE MOD (SUBSTR (phone_number, -1), 2) != 0 AND INSTR (phone_number,'.',1,3) = 0 AND INSTR (phone_number,'.',1,2) > 0; 

 SELECT * FROM employees WHERE LENGTH (SUBSTR (job_id, INSTR (job_id, '_') + 1)) > 3 AND SUBSTR (job_id, INSTR (job_id, '_') + 1) != 'CLERK'; 

 SELECT phone_number, REPLACE (phone_number, '.', '-') new_phone_number FROM employees; 

 SELECT * FROM employees WHERE TO_CHAR (hire_date, 'DD') = '01'; 

 SELECT * FROM employees WHERE TO_CHAR (hire_date, 'YYYY') = '2008'; 

 SELECT TO_CHAR (SYSDATE, 'fm""Tomorrow is ""Ddspth ""day of"" Month') info FROM DUAL; 

 SELECT first_name, TO_CHAR (hire_date, 'fmddth ""of"" Month, YYYY') hire_date FROM employees; 

 SELECT first_name, TO_CHAR (salary + salary * 0.20, 'fm$999,999.00') new_salary FROM employees; 

 SELECT * FROM employees WHERE hire_date BETWEEN TO_DATE ('01.02.2007', 'DD.MM.YYYY') AND LAST_DAY (TO_DATE ('01.02.2007', 'DD.MM.YYYY')); SELECT * FROM employees WHERE to_char(hire_date,'MM.YYYY') = '02.2007'; 

 SELECT SYSDATE now, SYSDATE + 1 / (24 * 60 * 60) plus_second, SYSDATE + 1 / (24 * 60) plus_minute, SYSDATE + 1 / 24 plus_hour, SYSDATE + 1 plus_day, ADD_MONTHS (SYSDATE, 1) plus_month, ADD_MONTHS (SYSDATE, 12) plus_year FROM DUAL; 

 SELECT first_name, salary, TO_CHAR (salary + salary * NVL (commission_pct, 0), 'fm$99,999.00') full_salary FROM employees; 

 SELECT first_name, commission_pct, NVL2 (commission_pct, 'Yes', 'No') has_bonus FROM employees; 

 SELECT first_name, salary, CASE WHEN salary < 5000 THEN 'Low' WHEN salary >= 5000 AND salary < 10000 THEN 'Normal' WHEN salary >= 10000 THEN 'High' ELSE 'Unknown' END salary_level FROM employees; 

 SELECT country_name country, DECODE (region_id, 1, 'Europe', 2, 'America', 3, 'Asia', 4, 'Africa', 'Unknown') region FROM countries; SELECT country_name country, CASE region_id WHEN 1 THEN 'Europe' WHEN 2 THEN 'America' WHEN 3 THEN 'Asia' WHEN 4 THEN 'Africa' ELSE 'Unknown' END region FROM countries; 

  SELECT department_id, MIN (salary) min_salary, MAX (salary) max_salary, MIN (hire_date) min_hire_date, MAX (hire_date) max_hire_Date, COUNT (*) count FROM employees GROUP BY department_id order by count(*) desc; 

 SELECT SUBSTR (first_name, 1, 1) first_char, COUNT (*) FROM employees GROUP BY SUBSTR (first_name, 1, 1) HAVING COUNT (*) > 1 ORDER BY 2 DESC; 

 SELECT department_id, salary, COUNT (*) FROM employees GROUP BY department_id, salary HAVING COUNT (*) > 1; 

 SELECT TO_CHAR (hire_Date, 'Day') day, COUNT (*) FROM employees GROUP BY TO_CHAR (hire_Date, 'Day') ORDER BY 2 DESC; 

 SELECT TO_CHAR (hire_date, 'YYYY') year, COUNT (*) FROM employees GROUP BY TO_CHAR (hire_date, 'YYYY'); 

 SELECT COUNT (COUNT (*)) department_count FROM employees WHERE department_id IS NOT NULL GROUP BY department_id; 

  SELECT department_id FROM employees GROUP BY department_id HAVING COUNT (*) > 30; 

  SELECT department_id, ROUND (AVG (salary)) avg_salary FROM employees GROUP BY department_id; 

  SELECT region_id FROM countries GROUP BY region_id HAVING SUM (LENGTH (country_name)) > 60; 

  SELECT department_id FROM employees GROUP BY department_id HAVING COUNT (DISTINCT job_id) > 1; 

  SELECT manager_id FROM employees GROUP BY manager_id HAVING COUNT (*) > 5 AND SUM (salary) > 50000; 

  SELECT manager_id, AVG (salary) avg_salary FROM employees WHERE commission_pct IS NULL GROUP BY manager_id HAVING AVG (salary) BETWEEN 6000 AND 9000; 

 SELECT MAX (salary) max_salary FROM employees WHERE job_id LIKE '%CLERK'; SELECT MAX (salary) max_salary FROM employees WHERE SUBSTR (job_id, -5) = 'CLERK'; 

  SELECT MAX (AVG (salary)) FROM employees GROUP BY department_id; 

  SELECT LENGTH (first_name), COUNT (*) FROM employees GROUP BY LENGTH (first_name) HAVING LENGTH (first_name) > 5 AND COUNT (*) > 20 ORDER BY LENGTH (first_name); SELECT LENGTH (first_name), COUNT (*) FROM employees WHERE LENGTH (first_name) > 5 GROUP BY LENGTH (first_name) HAVING COUNT (*) > 20 ORDER BY LENGTH (first_name); 

  SELECT region_name, COUNT (*) FROM employees e JOIN departments d ON (e.department_id = d.department_id) JOIN locations l ON (d.location_id = l.location_id) JOIN countries c ON (l.country_id = c.country_id) JOIN regions r ON (c.region_id = r.region_id) GROUP BY region_name; 

 SELECT First_name, Last_name, Department_name, Job_id, street_address, Country_name, Region_name FROM employees e JOIN departments d ON (e.department_id = d.department_id) JOIN locations l ON (d.location_id = l.location_id) JOIN countries c ON (l.country_id = c.country_id) JOIN regions r ON (c.region_id = r.region_id); 

  SELECT man.first_name, COUNT (*) FROM employees emp JOIN employees man ON (emp.manager_id = man.employee_id) GROUP BY man.first_name HAVING COUNT (*) > 6; 

 SELECT emp.first_name FROM employees emp LEFT JOIN employees man ON (emp.manager_id = man.employee_id) WHERE man.FIRST_NAME IS NULL; SELECT first_name FROM employees WHERE manager_id IS NULL; 

 SELECT first_name, NVL2 ( end_date, TO_CHAR (end_date, 'fm""Left the company at"" DD ""of"" Month, YYYY'), 'Currently Working') status FROM employees e LEFT JOIN job_history j ON (e.employee_id = j.employee_id); 

  SELECT first_name FROM employees JOIN departments USING (department_id) JOIN locations USING (location_id) JOIN countries USING (country_id) JOIN regions USING (region_id) WHERE region_name = 'Europe'; SELECT first_name FROM employees e JOIN departments d ON (e.department_id = d.department_id) JOIN locations l ON (d.location_id = l.location_id) JOIN countries c ON (l.country_id = c.country_id) JOIN regions r ON (c.region_id = r.region_id) WHERE region_name = 'Europe'; 

 SELECT department_name, COUNT (*) FROM employees e JOIN departments d ON (e.department_id = d.department_id) GROUP BY department_name HAVING COUNT (*) > 30; 

 SELECT first_name FROM employees e LEFT JOIN departments d ON (e.department_id = d.department_id) WHERE d.department_name IS NULL; SELECT first_name FROM employees WHERE department_id IS NULL; 

 SELECT department_name FROM employees e RIGHT JOIN departments d ON (e.department_id = d.department_id) WHERE first_name IS NULL; 

 SELECT man.first_name FROM employees emp RIGHT JOIN employees man ON (emp.manager_id = man.employee_id) WHERE emp.FIRST_NAME IS NULL; 

 SELECT first_name, job_title, department_name FROM employees e JOIN jobs j ON (e.job_id = j.job_id) JOIN departments d ON (d.department_id = e.department_id); 

 SELECT emp.* FROM employees emp JOIN employees man ON (emp.manager_id = man.employee_id) WHERE TO_CHAR (man.hire_date, 'YYYY') = '2005' AND emp.hire_date < TO_DATE ('01012005', 'DDMMYYYY'); 

 SELECT emp.* FROM employees emp JOIN employees man ON (emp.manager_id = man.employee_id) JOIN jobs j ON (emp.job_id = j.job_id) WHERE TO_CHAR (man.hire_date, 'MM') = '01' AND LENGTH (j.job_title) > 15; 

 SELECT * FROM employees WHERE LENGTH (first_name) = (SELECT MAX (LENGTH (first_name)) FROM employees); 

 SELECT * FROM employees WHERE salary > (SELECT AVG (salary) FROM employees); 

 SELECT city FROM employees e JOIN departments d ON (e.department_id = d.department_id) JOIN locations l ON (d.location_id = l.location_id) GROUP BY city HAVING SUM (salary) = ( SELECT MIN (SUM (salary)) FROM employees e JOIN departments d ON (e.department_id = d.department_id) JOIN locations l ON (d.location_id = l.location_id) GROUP BY city); 

 SELECT * FROM employees WHERE manager_id IN (SELECT employee_id FROM employees WHERE salary > 15000) 

 SELECT * FROM departments WHERE department_id NOT IN (SELECT department_id FROM employees WHERE department_id IS NOT NULL); 

 SELECT * FROM employees WHERE employee_id NOT IN (SELECT manager_id FROM employees WHERE manager_id IS NOT NULL) 

 SELECT * FROM employees e WHERE (SELECT COUNT (*) FROM employees WHERE manager_id = e.employee_id) > 6; 

 SELECT * FROM employees WHERE department_id = (SELECT department_id FROM departments WHERE department_name = 'IT'); 

 SELECT first_name, (SELECT job_title FROM jobs WHERE job_id = e.job_id) job_title, (SELECT department_name FROM departments WHERE department_id = e.department_id) department_name FROM employees e; 

 SELECT * FROM employees WHERE manager_id IN (SELECT employee_id FROM employees WHERE TO_CHAR (hire_date, 'YYYY') = '2005') AND hire_date < TO_DATE ('01012005', 'DDMMYYYY'); 

 SELECT * FROM employees e WHERE manager_id IN (SELECT employee_id FROM employees WHERE TO_CHAR (hire_date, 'MM') = '01') AND (SELECT LENGTH (job_title) FROM jobs WHERE job_id = e.job_id) > 15;