Грубер Мартин
Шрифт:
Глава 13.
1. SELECT * FROM Customers WHERE rating >=ANY
* (SELECT rating FROM Customers WHERE snum=1002);
cnum cname city rating snum
2002 Giovanni Rome 200 1003
2003 Liu San Jose 200 1002
2004 Grass Berlin 300 1002
* 2008 Cisneros SanJose 300 1007
SELECT * FROM Salespeople WHERE city < > ALL
(SELECT city FROM Customers);
или
SELECT * FROM Salespeople WHERE NOT city=ANY
* (SELECT city FROM Customers);
SELECT * FROM Orders WHERE amt > ALL (SELECT amt
FROM Orders a, Customers b WHERE a.cnum=b.cnum
* AND b.city='London');
SELECT * FROM Orders WHERE amt > (SELECT MAX (amt)
FROM Orders a, Customers b WHERE a.cnum=b.cnum
* AND b.city='London');
Глава 14.
SELECT cname, city, rating, 'High Rating' FROM Customers
WHERE rating >=200
UNION
SELECT cname, city, rating, ' Low Ratlng'
FROM Customers WHERE rating < 200;
или
SELECT cname, city, rating, 'High Rating'
FROM Customers WHERE rating >=200
UNION
SELECT cname, city, rating, ' Low Rating'
FROM Customers WHERE NOT rating >=200;
Различие между этими двумя предложениями, в форме второго предиката.
* Обратите внимание что, в обоих случаях, строка "Low Rating" имеет в начале дополнительный пробел для того чтобы совпадать со строкой "High Rating" по длине.
SELECT cnum, cname FROM Customers a
WHERE 1 < (SELECT COUNT (-)
FROM Orders b WHERE a.cnum=b.cnum)
UNION
SELECT snum, sname
FROM Salespeople a WHERE 1 <(SELECT COUNT (*) FROM Orders b
WHERE a.snum=b.snum)
* ORDER BY 2;
SELECT snum FROM Salespeople WHERE city='San Jose'
UNION
(SELECT cnum FROM Customers WHERE city='San Jose'
UNION ALL
* SELECT onum FROM Orders WHERE odate=10/03/1990);
Глава 15.
INSERT INTO Salespeople (city, cname, comm, cnum)
* VALUES ('San Jose', 'Blanco', NULL, 1100);
* DELETE FROM Orders WHERE cnum=2006;
* UPDATE Customers SET rating=rating + 100 WHERE city='Rome';
* UPDATE Customers SET snum=1004 WHERE snum=1002;
Глава 16.
INSERT INTO Multicust
SELECT * FROM Salespeople WHERE 1 < (SELECT COUNT (*)
* FROM Customers WHERE Customers.snum=Salespeople.snum);
DELETE FROM Customers WHERE NOT EXISTS
* (SELECT * FROM Orders WHERE cnum=Customers.cnum);
UPDATE Salespeople SET comm=comm + (comm * .2)
WHERE 3000 < (SELECT SUM (amt) FROM Orders
WHERE snum=Salespeople.snum);
В более сложный вариант этой команды можно было бы вставить проверку чтобы убедиться, что значения комиссионных не превышают 1.0 (100 % ):
UPDATE Salespeople SET comm=comm + (comm * .2)
WHERE 3000 < (SELECT SUM (amt)
FROM Orders WHERE snum=Salespeople.snum)
AND comm + (comm * .2) < 1.0;
* Эти проблемы могут иметь другие, такие же хорошие решения.
Глава 17.
CREATE TABLE Customers (cnum integer,
cname char(10), city char(10),
* rating integer, snum integer);
CREATE INDEX Datesearch ON Orders(odate);
* (Все индексные имена используемые в этих ответах - произвольные. )
* CREATE UNIQUE INDEX Onumkey ON Orders(onum);
* CREATE INDEX Mydate ON Orders(snum, odate);
* CREATE UNIQUE INDEX Combination ON Customers(snum, rating);
Глава 18.
CREATE TABLE Orders (onum integer NOT NULL PRIMARY KEY,
amt decimal, odate date NOT NULL,
cnum integer NOT NULL, snum integer NOT NULL,
UNIOUE (snum, cnum));
или
CREATE TABLE Orders (onum integer NOT NULL UNIQUE,
amt decimal, odate date NOT NULL,
cnum integer NOT NULL, snum integer NOT NULL,