Nima uchun loyihalash kerak

CREATE TABLE buyurtmalar_yomon (
    id              INT PRIMARY KEY,
    mijoz_ismi      VARCHAR(100),
    mijoz_telefoni  VARCHAR(20),
    mijoz_shahri    VARCHAR(50),
    mahsulot_nomi   VARCHAR(100),
    mahsulot_narxi  DECIMAL(10, 2),
    soni            INT,
    sana            DATE
);

INSERT INTO buyurtmalar_yomon VALUES
(1, 'Husanboy Qodirov', '901234567', 'Namangan', 'Noutbuk', 8000000, 1, '2026-01-10'),
(2, 'Husanboy Qodirov', '901234567', 'Namangan', 'Sichqoncha', 150000, 2, '2026-01-10'),
(3, 'Malika Yusupova',  '911112233', 'Farg''ona', 'Noutbuk', 8000000, 1, '2026-02-05'),
(4, 'Husanboy Qodirov', '901234567', 'Namangan', 'Klaviatura', 300000, 1, '2026-03-01');

SELECT mijoz_ismi, mijoz_telefoni, mahsulot_nomi
FROM buyurtmalar_yomon
ORDER BY id;

-- Husanboy telefon raqamini o'zgartirdi.
-- Dasturchi shoshib, faqat bitta qatorni yangiladi:
UPDATE buyurtmalar_yomon
SET mijoz_telefoni = '999999999'
WHERE id = 1;

SELECT DISTINCT mijoz_ismi, mijoz_telefoni
FROM buyurtmalar_yomon
WHERE mijoz_ismi = 'Husanboy Qodirov';

CREATE TABLE mijozlar (
    id       INT PRIMARY KEY AUTO_INCREMENT,
    ism      VARCHAR(100) NOT NULL,
    telefon  VARCHAR(20)  NOT NULL,
    shahar   VARCHAR(50)
);

CREATE TABLE mahsulotlar (
    id    INT PRIMARY KEY AUTO_INCREMENT,
    nom   VARCHAR(100)   NOT NULL,
    narx  DECIMAL(10, 2) NOT NULL
);

CREATE TABLE buyurtmalar (
    id         INT PRIMARY KEY AUTO_INCREMENT,
    mijoz_id   INT  NOT NULL,
    sana       DATE NOT NULL,
    FOREIGN KEY (mijoz_id) REFERENCES mijozlar(id)
);

CREATE TABLE buyurtma_qatorlari (
    buyurtma_id   INT NOT NULL,
    mahsulot_id   INT NOT NULL,
    soni          INT NOT NULL,
    PRIMARY KEY (buyurtma_id, mahsulot_id),
    FOREIGN KEY (buyurtma_id) REFERENCES buyurtmalar(id),
    FOREIGN KEY (mahsulot_id) REFERENCES mahsulotlar(id)
);

SELECT TABLE_NAME AS jadval
FROM information_schema.TABLES
WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME <> 'buyurtmalar_yomon'
ORDER BY BINARY TABLE_NAME;

INSERT INTO mijozlar (ism, telefon, shahar) VALUES
    ('Husanboy Qodirov', '901234567', 'Namangan'),
    ('Malika Yusupova',  '911112233', 'Farg''ona');

INSERT INTO mahsulotlar (nom, narx) VALUES
    ('Noutbuk', 8000000), ('Sichqoncha', 150000), ('Klaviatura', 300000);

-- Telefon raqamini o'zgartirish - BITTA qator
UPDATE mijozlar SET telefon = '999999999' WHERE ism = 'Husanboy Qodirov';

SELECT ism, telefon FROM mijozlar ORDER BY id;

-- Sxema haqidagi ma'lumotni ko'rish
SELECT COLUMN_NAME AS ustun, DATA_TYPE AS turi, IS_NULLABLE AS null_mumkinmi
FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'mijozlar'
ORDER BY ORDINAL_POSITION;