Reja: sql ning ichki tillari sql ma`lumot toifalari

SELECT operatori

SELECT (tanlash) SQL tilining eng muxim va ko‘p ishlatiladigan opеratori hisoblanadi. U ma’lumotlar bazasi jadvalidan axborotlarni tanlab olish uchun mo‘ljallangan.

SELECT opеratori sodda holda quyidagi ko‘rinishda yoziladi.

SELECT [DISTINCT] <atributlar ro‘yxati>

FROM <jadvallar ro‘yxati>

[WHERE <tanlash sharti>]

[ORDER BY < atributlar ro‘yxati >]

[GROUP BY < atributlar ro‘yxati >]

[HAVING <shart> ]

[UNION <ON SELECT opеratorli ifoda> ] ;

Oddiy SQL so`rovlari

PName	Price	Category	Manufacturer
Gizmo	$19.99	Gadgets	GizmoWorks
Powergizmo	$29.99	Gadgets	GizmoWorks
SingleTouch	$149.99	Photography	Canon
MultiTouch	$203.99	Household	Hitachi

SELECT * FROM Product WHERE category=‘Gadgets’

Product

PName	Price	Category	Manufacturer
Gizmo	$19.99	Gadgets	GizmoWorks
Powergizmo	$29.99	Gadgets	GizmoWorks

“tanlash”

PName	Price	Category	Manufacturer
Gizmo	$19.99	Gadgets	GizmoWorks
Powergizmo	$29.99	Gadgets	GizmoWorks
SingleTouch	$149.99	Photography	Canon
MultiTouch	$203.99	Household	Hitachi

SELECT PName, Price, Manufacturer FROM Product WHERE Price > 100

Product

PName	Price	Manufacturer
SingleTouch	$149.99	Canon
MultiTouch	$203.99	Hitachi

“tanlash” and

“solishtirish”

Oddiy SQL so`rovlari

LIKE operatori

• % = Berkitilgan simvollar o`rnida qo`llaniladi.

SELECT * FROM Products WHERE PName LIKE ‘%gizmo%’

PName	Price	Category	Manufacturer
Gizmo	$19.99	Gadgets	GizmoWorks
Powergizmo	$29.99	Gadgets	GizmoWorks
SingleTouch	$149.99	Photography	Canon
MultiTouch	$203.99	Household	Hitachi

Product

PName	Price	Manufacturer
Powergizmo	$29.99	GizmoWork

“tanlash” and

“solishtirish”

SELECT Category

FROM Product

ORDER BY PName

PName	Price	Category	Manufacturer
Gizmo	$19.99	Gadgets	GizmoWorks
Powergizmo	$29.99	Gadgets	GizmoWorks
SingleTouch	$149.99	Photography	Canon
MultiTouch	$203.99	Household	Hitachi

?

SELECT DISTINCT category

FROM Product

ORDER BY category

SELECT DISTINCT category

FROM Product

ORDER BY PName

?

?

Kalitlar

PName	Price	Category	Manufacturer
Gizmo	$19.99	Gadgets	GizmoWorks
Powergizmo	$29.99	Gadgets	GizmoWorks
SingleTouch	$149.99	Photography	Canon
MultiTouch	$203.99	Household	Hitachi

Product

Company

CName	StockPrice	Country
GizmoWorks	25	USA
Canon	65	Japan
Hitachi	15	Japan

Key

Foreign key

UPDATE командаси жадвал сатрлари ёки мавжуд сатрни баъзи бир ёки барча майдонларини қийматини тиклаш, яъни ўзгартириш имконини беради. Масалан: UNIVERSITET1 жадвалидаги, барча университетларини рейтингини 200 қийматга ўзгартириш учун қуйидаги конструкцияни ишлатиш мумкин:

UPDATE командаси жадвал сатрлари ёки мавжуд сатрни баъзи бир ёки барча майдонларини қийматини тиклаш, яъни ўзгартириш имконини беради. Масалан: UNIVERSITET1 жадвалидаги, барча университетларини рейтингини 200 қийматга ўзгартириш учун қуйидаги конструкцияни ишлатиш мумкин:

UPDATE UNIVERSITY1 SET RATING=200;

Foydalanilgan adabiyotlar

• Chetverikov V.N. i drugiye ‘Bazы i banki dannыx’ Moskva, VSh, 1987g.
• Klivert C. Yensiklopediya polzovatelya Delphi, Kiyev, 1996g.
• A.Ya.Arxangelskiy Delphi 7, Moskva, izd. ‘Binom’, 2003 g.
• T. Konnolli, K. Bregg. Bazы dannыx. Universitet Peysli, Shotlandiya, izd M SPB Kiyev, 2003g.
• Grigorьyev Yu.A., Revunkov G.I.. Banki dannыx. M.: Izd. MGTU im. Baumana, 2002.
• Rob P. Sistemы baz dannыx: proyektirovaniye, realizatsiya i upravleniye (5-ye izdaniye) izdatelьstvo ‘BXV - Sankt-Peterburg’ ·1200 str, 2003 g. ·.
• http://www.w3schools.com
• http://www.sql-tutorial.ru
• http://pitbooks.ru
• http://www.torryentino.ru