Oracle Academy

Prof. Carmen PopescuOracle Academy Lead Adjunct

Forma generala a comenzii SELECT

SELECT expresiiFROM tabeleWHERE conditii

In clauza select pot aparea coloane, sau expresii

Ordinea operatorilor: * / + -Operatorii logici: AND, OR (in

aceasta ordine)

BETWEENSELECT * from employeesWHERE department_id BETWEEN 10 AND

30SELECT * from employeesWHERE department_id >=10 AND department_id<=30

Departamentul 20 ESTE afisat

INSELECT * from employeesWHERE department_id IN (10,30)SELECT * from employeesWHERE department_id=10 ORdepartment_id=30

Departamentul 20 NU ESTE afisat

NULL

5+NULL => NULL- La ordonare crescatoare

valorile NULL sunt puse la sfarsit

- La ordonare descrescatoare NULL apare la inceput

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 SalaryFROM employees=> EROARE

ALIAS DE COLOANA (AS)SELECT first_name||’ ’||last_name AS NumeleFROM employees

SELECT first_name||’ ’||last_name AS ”Numele”FROM employees

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

DESCRIBE

LIKESELECT * from employeesWHERE first_name LIKE ’%a%’- afiseaza toate persoanele cu un ’a’

oriunde in prenumeSELECT * from employeesWHERE first_name LIKE ’_ _a%’- afiseaza persoanele cu un a pe a

treia pozitie din nume

% - oricate caractere (inclusiv nici unul)

_ - un singur caracter

LIKESELECT * from employeesWHERE 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.

ORDER BYSELECT * FROM employeesORDER BY last_name ASC, salary DESC

SELECT first_name,salary, department_idFROM employeesORDER BY 2

Se sorteaza dupa a doua expresie din clauza SELECT, adica dupa salary