GROUP BY

SQL GROUP BY Bayonoti

GROUP BY bayonoti bir xil qiymatlarga ega bo'lgan qatorlarni umumiy qatorlarga guruhlaydi, masalan "har bir mamlakatdagi mijozlar sonini topish".

GROUP BY bayonoti ko'pincha agregat funksiyalar (COUNT(), MAX(), MIN(), SUM(), AVG()) bilan birga ishlatiladi, natija to'plamini bir yoki bir nechta ustunlar bo'yicha guruhlash uchun.

GROUP BY Sintaksisi

SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
ORDER BY column_name(s);

Demo Ma'lumotlar Bazasi

Ushbu o'quv qo'llanmada Northwind namunaviy ma'lumotlar bazasidan "Customers" jadvalidan bir tanlov:

SQL GROUP BY Misollari

Quyidagi SQL bayonoti har bir mamlakatdagi mijozlar sonini ro'yxatga oladi:

SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country;

Quyidagi SQL bayonoti har bir mamlakatdagi mijozlar sonini yuqoridan pastga tartibda ro'yxatga oladi:

SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
ORDER BY COUNT(CustomerID) DESC;

Demo Ma'lumotlar Bazasi

Ushbu o'quv qo'llanmada Northwind namunaviy ma'lumotlar bazasidan "Orders" jadvalidan bir tanlov:

Va "Shippers" jadvalidan bir tanlov:

GROUP BY JOIN Bilan Misol

Quyidagi SQL bayonoti har bir yetkazib beruvchi tomonidan yuborilgan buyurtmalar sonini ro'yxatga oladi:

SELECT Shippers.ShipperName, COUNT(Orders.OrderID) AS NumberOfOrders
FROM Orders
LEFT JOIN Shippers ON Orders.ShipperID = Shippers.ShipperID
GROUP BY ShipperName;