SQLda matematik funksiyalar SQL tilida matematik funksiyalaridan quyidagilar ishlatiladi

SELECT ROUND(235.415, 2); 235.42

POWER(son, daraja) – sonni ko’rsatilgan darajaga ko’taradi;

SELECT POWER (3,2); 32

SQRT(son) – sondan kvadrat ildiz chiqaradi;

SELECT SQRT(64);

SIN(burchak) – radianlarda ifodalangan burchak sinusini hisoblaydi;

SQL da triggerlar

• Trigger - SQL da Trigger nomli
• ob'ekt bo'lib, jadvalda o’zgarishdan
• oldin yoki keyin ishga tushadi

• CREATE TRIGGER Trigger_misol
• AFTER INSERT ON students
• FOR EACH ROW
• BEGIN
• -- Trigger tanasi
• -- Yozilgan SQL kod
• INSERT INTO yoshlar (ustun_1, ustun_2)
• VALUES (NEW.ustun_1, NEW.ustun_2);
• END

SQL da trigger

• Ushbu misolda 2 ta jadval Murodilloyevtoxirjon , person_archive nomli jadvallar yaratilgan. Ushbu SQL kodi ishga tushiriladi va ma’lumot kiritish jarayonida age<25 bo’lsa, ma’lumot kiritilmaydi va ‘Person must be older than 25’ degan yozuv chiqadi va kiritilgan ma’lumotlarni jadvalga qo’shmaydi. Sababi trigger yaratganimizda BEFORE INSERT degan buyruqni yozganimiz sababli. Xuddi shu erga boshqa triggerlarni xam yozsa bo’ladi. Masalan AFTER INSERT. Ma’lumot kiritiladi va tegishli kod bajariladi va ma’lumot beriladi. Kodini yozib ber

• -- Trigger BEFORE INSERT
• CREATE TRIGGER age_check
• BEFORE INSERT ON person_archive
• FOR EACH ROW
• BEGIN
• IF NEW.age < 25 THEN
• SIGNAL SQLSTATE '45000'
• SET MESSAGE_TEXT = 'Person must be older than 25';
• END IF;
• END;
• -- Trigger AFTER INSERT
• CREATE TRIGGER after_insert_example
• AFTER INSERT ON person_archive
• FOR EACH ROW
• BEGIN
• -- Masalan: INSERT INTO Murodilloyevtoxirjon (column1, column2, ...) VALUES (NEW.column1, NEW.column2, ...);
• END