SQL asoslari: SELECT, WHERE, ORDER BY

SQL (Structured Query Language) — ma'lumotlar bazasi bilan ishlash tili.

SELECT — ma'lumot olish

-- Barcha ustunlar
SELECT * FROM talabalar;

-- Muayyan ustunlar
SELECT ism, familiya, yosh FROM talabalar;

-- Alias (taxallus)
SELECT ism AS to'liq_ism, yosh AS vaqt FROM talabalar;

WHERE — filtrlash

-- Tenglik
SELECT * FROM talabalar WHERE shahar = 'Toshkent';

-- Taqqoslash
SELECT * FROM mahsulotlar WHERE narx > 50000;

-- AND va OR
SELECT * FROM talabalar 
WHERE yosh >= 18 AND yosh <= 30;

SELECT * FROM mahsulotlar 
WHERE kategoriya = 'Kitob' OR kategoriya = 'Elektronika';

-- IN operatori
SELECT * FROM talabalar 
WHERE shahar IN ('Toshkent', 'Samarkand', 'Buxoro');

-- BETWEEN
SELECT * FROM mahsulotlar 
WHERE narx BETWEEN 10000 AND 100000;

-- LIKE (qidirish)
SELECT * FROM talabalar WHERE ism LIKE 'A%';    -- A bilan boshlanadi
SELECT * FROM talabalar WHERE ism LIKE '%ali';   -- ali bilan tugaydi

ORDER BY — tartiblash

-- O'sish tartibida
SELECT * FROM mahsulotlar ORDER BY narx ASC;

-- Kamayish tartibida
SELECT * FROM mahsulotlar ORDER BY narx DESC;

-- Bir nechta ustun bo'yicha
SELECT * FROM talabalar ORDER BY familiya ASC, ism ASC;

LIMIT va OFFSET

-- Faqat 10 ta qator
SELECT * FROM mahsulotlar LIMIT 10;

-- 11-20 qatorlar (sahifalash)
SELECT * FROM mahsulotlar LIMIT 10 OFFSET 10;