Convert from SQL to XQuery

Question

Hi there,
I am a total novice at XQuery. Please could someone convert the following SQL queries into XQuery form for me? I would be ever so greatfull.
The following SQL makes use of the Microsoft Northwind database.
--SQL QUERY 1
--postal address of all customers (for some kind of mail shot)
SELECT Customers.CompanyName, Customers.Address, Customers.City, Customers.[Postal Code], Customers.Country
FROM Customers
--SQL QUERY 2
--all order shipped in year 1997
SELECT Customers.CompanyName, Orders.OrderID, Orders.ShippedDate
FROM Customers, Orders
WHERE
((Customers.CustomerID) = (Orders.CustomerID))
AND ((Customers.CompanyName)="Around the Horn")
AND ((Orders.ShippedDate) between #12/31/996# AND #12/31/1997#)
--SQL QUERY 3
--all orders which shipped after their required arrival date (late!!)
SELECT Customers.CompanyName, Orders.OrderID
FROM Customers, Orders
WHERE
((Customers.CustomerID) = (Orders.CustomerID))
AND ((Orders.ShippedDate) > (Orders.RequiredDate))
--SQL QUERY 4
--all orders with item quantities of over 100 (bulk discount?)
SELECT Customers.CompanyName, Orders.OrderID, OrderDetails.Quantity
FROM Orders, [Order Details] as OrderDetails, Customers
WHERE Customers.CustomerID = Orders.CustomerID
AND Orders.OrderID = OrderDetails.OrderID
AND OrderDetails.Quantity > 100
--SQL QUERY 5
--apply discount to all orders from above query
update [Order Details] as OrderDetails
Set OrderDetails.Discount = OrderDetails.Discount * 1.05
where OrderDetails.OrderID in
select Orders.OrderID
from Orders, [Order Details] as OrderDetails, Customers
where Customers.CustomerID = Orders.CustomerID
AND Orders.OrderID = OrderDetails.OrderID
AND OrderDetails.Quantity > 100
)

Answer 1

A follow-up question ...
If the table tblmtk for example, there are three rows like this:
WC        MPM        Valid_from
34819     1          2010-06-01
34819     2.5        2011-01-01
34819     1.5        2012-01-01If the value is outside of the validity period (valid_from) shall it take the last valid_from value. How?
select max(MPM) keep(dense_rank first order by case when valid_from  <= '2007-05-10' then valid_from else null end desc nulls last) r1
  from tblmtk
where wc = '34819'I want the result to look like this:
R1= 1.5
But now I get R = 2.5