Antwoorden

Vraag 6.1

Wat is de naam van de track die het langste duurt?

select name 
from Track 
where Milliseconds = (
    select max(Milliseconds) 
    from Track);

Vraag 6.2

Wat is de naam van de track die het kortste duurt?

select name 
from Track 
where Milliseconds = (
    select min(Milliseconds) 
    from Track);

Vraag 6.3

Welk album zijn nog nooit verkocht?

select name 
from track
where trackid not in (
    select t.trackid
    from Track as T, InvoiceLine as I
    where t.trackid = I.trackid);

Vraag 6.4

Wat is de duurste bestelling ooit geweest?

select invoiceID, sum(UnitPrice * Quantity) 
from InvoiceLine 
group by InvoiceID 
order by sum(UnitPrice  * Quantity) 
desc Limit 1;

Vraag 6.5

Welke klant heeft dat besteld?

select DISTINCT Customer.firstname, customer.lastname
from customer, Invoice, Invoiceline
where Customer.CustomerID = Invoice.CustomerID AND
    Invoice.InvoiceID = InvoiceLine.InvoiceID AND
    Invoice.InvoiceID = (
        select invoiceID
        from InvoiceLine 
        group by InvoiceID 
        order by sum(UnitPrice  * Quantity) 
        desc Limit 1);