Comenzi SQL de Selecție

Tabela A

a1 a2 a3 a4 a5 a6

Tabela B

b1 b2 b3 b4 b5 a1

Tabela C

c1 c2 c3 c4 C5 a1

SELECT [domeniu: ALL/DISTINCT/DISTINCTROW] lista selectie câmpuri

FROM nume tabela(e)

[WHERE criteriu de selectie]

[ORDER BY lista câmpuri criterii de ordonare {ASC/DESC}];

Exemple:

SELECT DISTINCTROW a1,a2

FROM A

SELECT DISTINCT a5

FROM A

WHERE a5>1000;

SELECT DISTINCT a5

FROM A

WHERE a5>1000 AND a3=”text”;

SELECT DISTINCT a5

FROM A

WHERE a5 (NOT) BETWEEN 1000 AND 10000;

SELECT DISTINCT a5

FROM A

WHERE a3 LIKE ”*text”;

SELECT a2,a4,a5

FROM A

WHERE a2 IN(1500, 13000, 14000)

ORDER BY a2 ASC, a5 DESC;

SELECT DISTINCTROW Max(a5) AS [a5_maxim], Min(a5) AS [a5_minim], Avg(a5) AS [a5_medie]

FROM A

SELECT COUNT(*) AS [Numar de tupluri]

FROM A

SELECT a1, a2, a3, a5, a6, IIF(a5>=a6;a5-a6;a6-a5) AS [functie conditionala]

FROM A

WHERE a2 IS NOT NULL;

Interogari de grupare

SELECT [domeniu: ALL/DISTINCT/DISTINCTROW] lista selectie câmpuri

FROM nume tabela(e)

[WHERE criteriu de selectie]

[GROUP BY câmp(uri) de grupare]

[HAVING criteriul câmpului de grupare]

[ORDER BY lista câmpuri criterii de ordonare {ASC/DESC}];

SELECT b1, b2, b4, b5, b3*b4 AS [produs b3 si b4]

FROM B

WHERE b2=”ctiteriu text”

GROUP BY b4

HAVING Sum(b3)>300000;

Interogari asociative clasice

SELECT [domeniu] lista selectie câmpuri din tabele diferite

FROM nume tabele

[WHERE criteriu de compunere

[ORDER BY lista câmpuri criterii de ordonare {ASC/DESC}];

SELECT A.a1, A.a2, B.b1, C.c1, C.c3

FROM A, B, C

WHERE A.a1=B.a1 AND B.a1=C.a1

ORDER BY C.c3;

Compuneri interne

SELECT [domeniu] lista selectie câmpuri din tabele diferite

FROM nume tabela_1

{INNER/LEFT/RIGHT} JOIN nume tabela_2

ON criteriu de asociere

[WHERE criteriu de compunere

[ORDER BY lista câmpuri criterii de ordonare {ASC/DESC}];

SELECT A.a5, B.b3, (A.a5*B.B3) AS [Produs]

FROM A

INNER JOIN B ON A.A1=B.A1

ORDER BY A.a5;

SELECT A.a1, A.a2, A.a5, B.b1, C.c1

FROM A

INNER JOIN (B INNER JOIN C ON B.a1=C.a1) ON

(A.a1=B.a1) AND (B.a10C.a1);