122. Sekin subquery ni qayta yozish

Quyidagi so'rov to'g'ri ishlaydi, lekin **har bir sotuvchi uchun jadvalni

uch marta** aylanib chiqadi:

SELECT s.name AS seller,
       (SELECT COUNT(*)  FROM orders o WHERE o.seller_id = s.id) AS orders_count,
       (SELECT SUM(amount) FROM orders o WHERE o.seller_id = s.id) AS revenue,
       (SELECT AVG(amount) FROM orders o WHERE o.seller_id = s.id) AS avg_check
FROM sellers s;

Xuddi shu natijani bitta JOIN va GROUP BY bilan oling.

Buyurtmasi yo'q sotuvchi ham chiqishi kerak: orders_count = 0,

revenue = 0, avg_check = 0.

avg_check 2 xonagacha yaxlitlansin.

Ustunlar: seller, orders_count, revenue, avg_check.

Saralash: revenue kamayish, keyin seller alifbo.

sellers: id INT PK, name VARCHAR

orders: id INT PK, seller_id INT, amount NUMERIC(12,2)

Jadval: sellers

Jadval: orders