SQL
, SQL- , , . . , SQL . ( ), , . SQL.
SQL , , :
- (exact numerics);
- (approximate numerics);
- (character strings);
- (bit strings);
- (datetimes);
- (intervals);
- (Booleans);
- (collection types);
- (anonymous row types);
- , (user-defined types);
- (reference types).
, , , , NULL.
T
SQL , . : (INTEGER SMALLINT) , (NUMERIC DECIMAL).
- INTEGER . ( ) . INTEGER.
- SMALLINT . , INTEGER. SMALLINT.
,
- NUMERIC. , , . NUMERIC (p, s), p ( ), s ( ). . NUMERIC NUMERIC (p). , , , , , . p s .
- DECIMAL. NUMERIC. , DECIMAL p, m, , , m > p. , ( ) . DECIMAL, DECIMAL (p) DECIMAL (p, s).
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SQL , . <, >, , . SQL . SQL .
- REAL. . , , , . REAL.
- DOUBLE PRECISION. , REAL. SQL . DOUBLE PRECISION.
- FLOAT. , p . , p. p . FLOAT (p), FLOAT. , .
SQL : CHARACTER ( CHAR), CHARACTER VARYING ( CHAR VARYING, VARCHAR) CHARACTER LARGE OBJECT ( CLOB).
- CHARACTER. . , , , ASCII. CHARACTER (x) CHARACTER. CHARACTER (1). CHARACTER (x) x . , , CHARACTER (8), , , .
- CHARACTER VARYING. CHARACTER VARYING (x) CHARACTER VARYING. CHARACTER VARYING (1). CHARACTER VARYING (x), , ( x ).
- , . .
- ( ||) , - , .
- (SUBSTRING) , , - .
- UPPER , - . LOWER, , .
- (CHARACTER_LENGTH, OCTET_LENGTH, BIT_LENGTH) , ( ) .
- (POSITION) S, S1 ( , ).
- CHARACTER LARGE OBJECT. , . CLOB (z), z . z , , , x, CHAR CHAR VARYING.
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