SQL Query Where Date = Today Minus 7 Days

declare @lastweek datetime
declare @now datetime
set @now = getdate()
set @lastweek = dateadd(day,-7,@now)

SELECT URLX, COUNT(URLx) AS Count
FROM ExternalHits
WHERE datex BETWEEN @lastweek AND @now
GROUP BY URLx
ORDER BY Count DESC; 

You can subtract 7 from the current date with this:

WHERE datex BETWEEN DATEADD(day, -7, GETDATE()) AND GETDATE()

Using dateadd to remove a week from the current date.

datex BETWEEN DATEADD(WEEK,-1,GETDATE()) AND GETDATE()