SOME ANY - ANY, SOME . . ; , , . ( 13.1):
SELECT * FROM Salespeople WHERE city = ANY (SELECT city FROM Customers);ANY , ( - city ), (ANY) .
=============== SQL Execution Log ============ | SELECT * | | FROM Salespeople | | WHERE city = ANY | | (SELECT city | | FROM Customers); | | ============================================= | | cnum cname city comm | | ----- -------- ---- -------- | | 1001 Peel London 0.12 | | 1002 Serres San Jose 0.13 | | 1004 Motika London 0.11 | =============================================13. 1: ANY
, , . EXISTS, , - , .
ALL
ALL, , . - , , , 13.9:
SELECT * FROM Customers WHERE rating > ALL (SELECT rating FROM Customers WHERE city = Rome): =============== SQL Execution Log ============ | | | SELECT * | | FROM Customers | | WHERE rating > ALL | | (SELECT rating | | FROM Customers | | WHERE city = 'Rome'); | | ============================================= | | cnum cname city rating snum | | ----- -------- ---- ------ ------ | | 2004 Grass Berlin 300 1002 | | 2008 Cisneros San Jose 300 1007 | =============================================13.9: ALL . . - Giovanni(200). , 200. ANY, EXISTS - ( 13.10):
SELECT * FROM Customers outer WHERE NOT EXISTS (SELECT * FROM Customers inner WHERE outer.rating < = inner.rating AND inner.city = 'Rome'); =============== SQL Execution Log ============ | | | SELECT * | | FROM Customers outer | | WHERE NOT EXISTS | | (SELECT * | | FROM Customers inner | | WHERE outer rating = inner.rating | | AND inner.city = 'Rome'); | | ============================================= | | cnum cname city rating snum | | ----- -------- ---- ------ ------ | | 2004 Grass Berlin 300 1002 | | 2008 Cisneros San Jose 300 1007 | =============================================13.10: EXISTS ALL
|
|
ANY ALL EXISTS (NULL)
NULL . SQL , - (NULL), ( 5). , , , , ALL ANY EXISTS. :
SELECT * FROM Customers WHERE rating > ANY (SELECT rating FROM Customers WHERE city = 'Rome');
14). SQL.
- ( ) . , , - , . - , , .
- (, ANSI ):
CREATE INDEX <INDEX name> ON <TABLE name>(<COLUMN name> [,<COLUMN name>]...);
- . . SQL , , . , , . :
DROP INDEX;.
15). SQL.
SQL-, .
<_>::=
CREATE TRIGGER _
BEFORE | AFTER <_>
ON <_>
[REFERENCING
<____>]
[FOR EACH { ROW | STATEMENT}]
[WHEN(_)]
<_>
, , :
UPDATE SET =-10
WHERE =3
:
- INSERT TRIGGER INSERT.
- UPDATE TRIGGER UPDATE.
- DELETE TRIGGER DELETE.
- , . DROP TRIGGER. Add_copies :
|
|
//
DROP TRIGGER Add_copies.
16). SQL.
:
(VIEW) - . - , . , - , . , , , - . , - , , .
?
, , - . - , . : - . - . DML , - . - , - ( , , ), . - , , - . .
CREATE VIEW
CREATE VIEW. CREATE VIEW ( ), , AS (), , :
CREATE VIEW Londonstaff AS SELECT * FROM Salespeople WHERE city = 'London';, Londonstaff. . , , , , , . ( 20.1):
SELECT * FROM Londonstaff;