Here's a shot in the dark:
USE NORTHWIND
SELECT
CustomerID
, COUNT(*) No_of_Orders
, DATEDIFF(d,MIN(OrderDate), MAX(OrderDate)) TimeSpan
, COUNT(*)*1.0 / DATEDIFF(d,MIN(OrderDate), MAX(OrderDate)) DailyOrder
FROM
Orders
WHERE CustomerID = 'ERNSH'
AND (OrderDate >='19960717' AND OrderDate <='19960723')
GROUP BY CustomerID
Btw, since this is an exercise given to you, don't you think you should find the solution yourself?
--
Frank Kalis
Microsoft SQL Server MVP
Webmaster: http://www.insidesql.org/blogs
My blog: http://www.insidesql.org/blogs/frankkalis/[/url]