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 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
where sales_rank <= 5
union
select *
from sales
where sales_rank >= ((select max(sales_rank) from sales)-5)
order by total_quantity desc;