Karpova_bazy_dannyh

71

EXECUTE

SQL,

.

-

.

SQL/89 :

CHARACTER(n) CHAR(d)

n . -

, , ,

, SQL1 ,

INT SMALLINT (), -

, INTEGER , , a SMALLINT

, .

, REAL.

SQL92 :

VARCHAR(n) .

NCHAR(N) .

NCHAR VARYING(n) .

I(n) .

BIT VARYING(n) .

DATE .

TIMESTAMP() .

INTERVAL .

-

. , ,

. MEMO

. -, , ORACLE

LONG, DB2 - LONG VARCHAR, SYBASE MS SQL Server TEXT.

,

.

D TIMESTAMP. -

, --

.

. .

:

, MS SQL Server Informix -

:

, -

, -

-

.

15 MAR 99

. SQL1 -

USER, , -

.

SQL , -

(+)

(-), (*) (/).

(/) . -

-

. SQL2 -

SQL1 , - -

, SQL2

.

BIT_LENGTH() ;

ST ( AS ) ,

;

CHAR_LENGTH() - ;

CONVERT( USJNG ) , -

TRANSLATE( USING ) , -

;

TRIM(BOTH FROM ) , -

;

TRIM(LEADING FROM ) ,

;

TRIM(TRAILING FROM ) , -

;

UPPER() - , .

SELECT

(Data Query Language) SQL - SELECT. -

WHERE -

, -

.

GROUP BY .

HAVING -,

.

ORDER BY , o -

, -

. , , -

, -

, ,

.

WHERE -

:

{=, <>, >, <, >=, <=},

.

Between A and 8 .

, ,

, .

IN () ,

. -

. NOT IN (), , .

LIKE NOT LIKE. LIKE

, , ,

, .

NOT LIKE . -

:

o (_) -

;

o (%) -

;

.

,

. -

:

<> IS NULL <> IS NOT NULL

».

.

, , -

.

,

(-

).

SELECT .

SELECT

. , SELECT *

FROM Rl, R2

R1 R2.

SELECT Rl A R2

FROM Rl R2

R1 R2, , -

, -

.

WHERE - , , - , ,

, .

:

4906

4807

, «-

» «». SELECT FROM R1

WHERE = "" AND = 5

:

. .

. .

,

, . SELECT .

FR0M R2, R3

WHERE R2. = R2.

WHERE R2 R3, -

WHERE -

,

R3, , -

.

:

. .

. .

. .

. .

. .

. .

. .

. .

. .

. .

. .

. .

. .

. A.

. .

. .

. .

. .

. .

. .

. .

. .

. .

. .

R, a b,

.

:

. .

, (

) (,

, , .

SQL

,

.