Напредни извештаи од базата (SQL и складирани процедури)

1. Приказ на доставувачи кои имаат доставено производи со информација за колку различни производи имаат доставено, количината на тие производи во сите магацини и во колку различни магацини ги има тие производи и вкупната количина што ја имаат нарачано клиентите.

SELECT s.supplierId, s.supplier_name, q1.products_count, q2.total_quantity_in_warehouses, COALESCE(COUNT(DISTINCT pw.warehouseId), 0) AS distinct_warehouses_count, COALESCE(SUM(oi.quantity), 0) AS total_quantity_in_order_items
FROM suppliers s
LEFT JOIN ( SELECT s.supplierId, COUNT(DISTINCT p.productId) AS products_count
FROM suppliers s
LEFT JOIN products p ON s.supplierId = p.supplierId
GROUP BY s.supplierId )
q1 ON s.supplierId = q1.supplierId

LEFT JOIN (
SELECT s.supplierId, COALESCE(SUM(pw.quantity), 0) AS total_quantity_in_warehouses
FROM suppliers s
LEFT JOIN products p ON s.supplierId = p.supplierId
LEFT JOIN products_in_warehouse pw ON p.productId = pw.productId
GROUP BY s.supplierId )
q2 ON s.supplierId = q2.supplierId

LEFT JOIN products p ON s.supplierId = p.supplierId
LEFT JOIN products_in_warehouse pw ON p.productId = pw.productId
LEFT JOIN order_item oi ON p.productId = oi.productId
GROUP BY s.supplierId, s.supplier_name, q1.products_count, q2.total_quantity_in_warehouses
HAVING q1.products_count > 0;

2. Извештај за првите и последните 5 производи рангирани според вкупната нарачана количина

WITH Sales_Table AS 
  (SELECT *, RANK () OVER (ORDER BY Total_Quantity DESC) Sales_Rank 
  FROM 
    (SELECT p.product_name, SUM (quantity) AS Total_Quantity 
    FROM order_item oi 
    JOIN products p on p.productid = oi.productid
    GROUP BY oi.productid, p.product_name
    ORDER BY Total_Quantity)
  )

SELECT * 
FROM Sales_Table 
WHERE Sales_Rank <= 5 
UNION
SELECT * 
FROM Sales_Table 
WHERE Sales_Rank >= ((SELECT MAX(Sales_Rank) FROM Sales_Table)-5)
ORDER BY Total_Quantity DESC;