SQLni bilasizmi?

Ha, SQL bilan ishlash tajribam bor, xususan Microsoft SQL Server bilan.

Asosiy tushunchalar va buyruqlar bilan tanishman:

• DDL (Data Definition Language): CREATE, ALTER, DROP.
• DML (Data Manipulation Language): SELECT, INSERT, UPDATE, DELETE.
• DCL (Data Control Language): GRANT, REVOKE.
• TCL (Transaction Control Language): COMMIT, ROLLBACK.

Murakkab so'rovlar yozishni bilaman:

• Birlashtirishlar (JOIN): INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL OUTER JOIN, CROSS JOIN.
• Guruhlash va filtrlar: GROUP BY, HAVING, WHERE.
• Subso'rovlar.
• Oyna funktsiyalari (Window Functions).
• Umumiy jadval ifodalari (CTE).

Shuningdek, indekslar (klasterli, klastersiz), tranzaktsiyalar, saqlangan protseduralar va triggerlar bilan tanishman. Ma'lumotlar bazalarining normalizatsiya tamoyillarini tushunaman.

Oddiy ma'lumotlarni tanlash uchun so'rov misoli:

SELECT  
    CustomerID, -- Mijoz identifikatori  
    CompanyName, -- Kompaniya nomi  
    ContactName -- Kontakt nomi  
FROM  
    Customers -- Mijozlar jadvalidan  
WHERE  
    Country = 'USA'; -- Mamlakat bo'yicha filtr  

JOIN va agregatsiya bilan so'rov misoli:

SELECT  
    p.ProductName, -- Mahsulot nomi  
    SUM(od.Quantity) AS TotalQuantitySold -- Sotilgan umumiy miqdor  
FROM  
    Products AS p -- Mahsulotlar jadvali  
INNER JOIN  
    OrderDetails AS od ON p.ProductID = od.ProductID -- Mahsulot ID bo'yicha birlashtirish  
GROUP BY  
    p.ProductName; -- Mahsulot nomi bo'yicha guruhlash