Raqamli texnologiyalar fakulteti amaliy matematika yo’nalishi topshiriqlari

vend_name
vend_name_upcase
Bear Emporium	BEAR EMPORIUM
Bears R Us	BEARS R US
Doll House Inc.	DOLL HOUSE INC.
Fun and Games	FUN AND GAMES
Furball Inc.	FURBALL INC.
Jouets et ours	JOUETS ET OURS

2) LOWER() funksiyasi
SELECT vend_name, LOWER(vend_name) AS vend_name_lowcase FROM Vendors ORDER BY vend_name;

vend_name	vend_name_lowcase
Bear Emporium	bear emporium
Bears R Us	bears r us
Doll House Inc.	doll house inc.
Fun and Games	fun and games
Furball Inc.	furball inc.
Jouets et ours	jouets et ours

2) LEFT() funksiyasi

SELECT FacultetNom LEFT(FacultetNom,3) AS QisqachaNom FROM facultet;



6.2. Raqamli funksiyalar

Funksiya	Qaytuvchi qiymat
ABS()	Sonning moduli
COS()	Berilgan burchakning kosinusi
EXP()	Berilgan sonning ko‘rsatkichi
PI()	soni
SIN()	Berilgan burchakning sinusi
SQRT()	Berilgan sonning kvadrat ildizi
TAN()	Berilgan burchakning tangensi

6.3. Jami hisob funksiyalari

Funksiya	Qaytuvchi qiymat
AVG()	Ustun bo’yicha qiymatlarning o’rtachasi
COUNT()	Ustundagi qatorlar soni
MAX()	Ustundagi eng katta qiymat
MIN()	Ustundagi eng kichik qiymat
SUM()	Ustundagi qiymatlar yig’indisi

Topshiriq. Yuqoridagi funksiyalarni jadvallarda qo’llab so’rovlar hosil qiling


7-TOPSHIRIQ. TRANZAKSIYALAR
Tranzaksiyalarni boshqarish. Tranzaksiyalarni boshqarish uchun quyidagi buyruqlardan foydalaniladi:


COMMIT - O'zgarishlarni saqlaydi
ROLLBACK - O'zgarishlarni qaytaradi (bekor qilish)
SAVEPOINT - Tranzaksiyalar guruhi orqaga qaytarishi mumkin bo'lgan nuqtani yaratadi
SET TRANSACTION - Tranzaksiya nomini joylashtiradi.

Tranzaktsiyalarni boshqarish buyruqlari faqat DML buyruqlari uchun ishlatiladi: INSERT, UPDATE, DELETE. Ularni jadval yaratish, o'zgartirish yoki yo'q qilish paytida ishlatib bo'lmaydi.

Misollar:

Ishni boshlashdan oldin, avtomatik tranzaktsiyalarni bajarilishini o'chirish uchun quyidagi buyruqni bajaring:

mysql> SET autocommit=0;

Aytaylik, bizda developers jadvali quyidagi yozuvlarni o'z ichiga oladi:

+----+-------------------+-----------+------------+--------+

| ID | NAME | SPECIALTY | EXPERIENCE | SALARY |
+----+-------------------+-----------+------------+--------+
| 1 | Eugene Suleimanov | Java | 2 | 2500 |
| 2 | Peter Romanenko | Java | 3 | 3500 |
| 3 | Andrei Komarov | C++ | 3 | 2500 |
| 4 | Konstantin Geiko | C# | 2 | 2000 |
| 5 | Asya Suleimanova | UI/UX | 2 | 1800 |
| 7 | Ivan Ivanov | C# | 1 | 900 |
| 8 | Ludmila Geiko | UI/UX | 2 | 1800 |
+----+-------------------+-----------+------------+--------+
Quyidagi buyruq bilan C ++ dasturchilarining barchasini o'chirib tashlang:

mysql> DELETE FROM developers

WHERE SPECIALTY = 'C++';

mysql> COMMIT;

Ushbu so'rovni bajarish natijasida bizning jadval quyidagi yozuvlarni o'z ichiga oladi:

+----+-------------------+-----------+------------+--------+
| ID | NAME | SPECIALTY | EXPERIENCE | SALARY |
+----+-------------------+-----------+------------+--------+
| 1 | Eugene Suleimanov | Java | 2 | 2500 |
| 2 | Peter Romanenko | Java | 3 | 3500 |
| 4 | Konstantin Geiko | C# | 2 | 2000 |
| 5 | Asya Suleimanova | UI/UX | 2 | 1800 |
| 7 | Ivan Ivanov | C# | 1 | 900 |
| 8 | Ludmila Geiko | UI/UX | 2 | 1800 |
+----+-------------------+-----------+------------+--------+

Endi