Я хотел бы создать ежемесячный отчет (MySQL)

Question

Я хотел бы создать ежемесячный отчет

Tables 
Product (id, name, price) 
Invoice (id, date) 
Invoice_item (id, invoice_id, product_id, quantity) 

Образец данных:

product 
id | name | price 
1 | apple | 10 
2 | beer | 20 
3 | shoe | 40 

invoice 
id | date 
1 | 2013-01-21 
2 | 2013-01-29 
3 | 2013-02-02 

invoice_item 
id | invoice_id | product_id | quantity 
1 | 1   | 1   | 2 
2 | 1   | 2   | 1 
3 | 2   | 3   | 1 
4 | 3   | 2   | 2 

Я хочу, чтобы этот результат:

product.id | product.name | year(invoice.date) | month(invoice.date) | count  | sum 
1   | apple  | 2013    | 01     | 2   | 20 
1   | apple  | 2013    | 02     | 0 (or null) | 0 (or null) 
2   | beer   | 2013    | 01     | 1   | 20 
2   | beer   | 2013    | 02     | 2   | 40 
3   | shoe   | 2013    | 01     | 1   | 40 
3   | shoe   | 2013    | 02     | 0 (or null) | 0 (or null) 

Вот код, который я сделал:

SELECT * FROM ( 
SELECT product prod, 
(SELECT date FROM invoice 
GROUP BY YEAR(date), MONTH(date)) grpdate) p 
LEFT JOIN invoice_item ii 
    ON ii.product_id = p.id 
LEFT JOIN invoice i 
    ON ii.invoice_id=i.id 
GROUP BY p.id, YEAR(date), MONTH(date), 
IF(YEAR(date) = YEAR(grpdate), YEAR(date), null), 
IF(MONTH(date) = MONTH(grpdate), MONTH(date), null) 

Answer 1

Вы должны быть в состоянии использовать следующее:

select 
    p.id, 
    p.name, 
    d.Year, 
    d.Month, 
    coalesce(i.TotalQuantity, 0) as TotalQuantity, 
    p.price * coalesce(i.TotalQuantity, 0) as TotalPrice 
from product p 
inner join 
(
    select distinct p.id, year(date) year, month(date) month 
    from invoice 
    cross join product p 
) d 
    on p.id = d.id 
left join 
(
    select ii.invoice_id, 
    ii.product_id, 
    year(i.date) Year, 
    month(i.date) Month, 
    sum(quantity) TotalQuantity 
    from invoice_item ii 
    inner join invoice i 
    on ii.invoice_id = i.id 
    group by ii.invoice_id, ii.product_id, year(i.date), month(i.date) 
) i 
    on p.id = i.product_id 
    and d.year = i.Year 
    and d.month = i.month; 

См SQL Fiddle with Demo. В результате этого запроса:

| ID | NAME | YEAR | MONTH | TOTALQUANTITY | TOTALPRICE | 
---------------------------------------------------------- 
| 1 | apple | 2013 |  1 |    2 |   20 | 
| 1 | apple | 2013 |  2 |    0 |   0 | 
| 2 | beer | 2013 |  1 |    1 |   20 | 
| 2 | beer | 2013 |  2 |    2 |   40 | 
| 3 | shoe | 2013 |  1 |    1 |   40 | 
| 3 | shoe | 2013 |  2 |    0 |   0 | 

Answer 2

Попробуйте ниже:

SELECT product.id, product.name, YEAR(invoice.date), MONTH(invoice.date), COUNT(*), SUM(invoice_item.price) 
FROM invoice_item , invoice, product 
WHERE invoice_item.invoice_id = invoice.id 
AND invoice_item.product_id = product.id 
GROUP BY YEAR(invoice.date), MONTH(invoice.date),product.id