Oracle Academy

1. Oracle Academy Prof. Carmen Popescu Oracle Academy Lead Adjunct

2. Forma generala a comenzii SELECT SELECT expresii FROM tabele WHERE conditii In clauza select pot aparea coloane, sau expresii Ordinea operatorilor: * / + - Operatorii logici: AND, OR (in aceasta ordine)

3. BETWEEN SELECT * from employees WHERE department_id BETWEEN 10 AND 30  SELECT * from employees WHERE department_id >=10 AND department_id<=30 Departamentul 20 ESTE afisat

4. IN SELECT * from employees WHERE department_id IN (10,30)  SELECT * from employees WHERE department_id=10 OR department_id=30 Departamentul 20 NU ESTE afisat

5. NULL 5+NULL => NULL • La ordonare crescatoare valorile NULL sunt puse la sfarsit • La ordonare descrescatoare NULL apare la inceput

6. ALIAS DE COLOANA (AS) SELECT salary+0.25*salary FROM employees SELECT salary+0.25*salary AS ”New Salary” FROM employees SELECT salary+0.25*salary AS New Salary FROM employees => EROARE

7. ALIAS DE COLOANA (AS) SELECT first_name||’ ’||last_name AS Numele FROM employees SELECT first_name||’ ’||last_name AS ”Numele” FROM employees

8. ALIAS DE COLOANA (AS) Ghilimelele la alias sunt obligatorii cand: • Aliasul e compus din doua sau mai multe cuvinte • Dorim ca aliasul sa fie scriscu litere mici

9. DESCRIBE

10. LIKE SELECT * from employees WHERE first_name LIKE ’%a%’ • afiseaza toate persoanele cu un ’a’ oriunde in prenume SELECT * from employees WHERE first_name LIKE ’_ _a%’ • afiseaza persoanele cu un a pe a treia pozitie din nume % - oricate caractere (inclusiv nici unul) _ - un singur caracter

11. LIKE SELECT * from employees WHERE job_title LIKE ’%\_ _ _’ ESCAPE ’\’ • afiseaza persoanele pt. care in job_title, dupa caracterul _ mai exista exact doua caractere • Cu clauza ESCAPE am precizat ca% sau _ precedate de \ vor fi tratate ca si caractere normale ce trebuie sa apara in text nu ca wildchar.

12. ORDER BY SELECT * FROM employees ORDER BY last_name ASC, salary DESC SELECT first_name,salary, department_id FROM employees ORDER BY 2 Se sorteaza dupa a doua expresie din clauza SELECT, adica dupa salary