Your database contains a table named Purchases. The table includes a DATETIME column named
PurchaseTime that stores the date and time each purchase is made. There is a non-clustered index
on the PurchaseTime column. The business team wants a report that displays the total number of
purchases made on the current day. You need to write a query that will return the correct results in
the most efficient manner. Which Transact-SQL query should you use?
A.
 SELECT COUNT(*)FROM 
Purchases WHERE 
PurchaseTime = 
CONVERT(DATE, GETDATE())
B.
 SELECT COUNT(*)FROM 
Purchases WHERE 
PurchaseTime = GETDATE()
C.
 SELECT COUNT(*)FROM 
Purchases WHERE 
CONVERT(VARCHAR, 
PurchaseTime, 112) = CONVERT(VARCHAR, GETDATE(), 112)
D.
 SELECT COUNT(*)FROM 
Purchases WHERE 
PurchaseTime >= 
CONVERT(DATE, GETDATE()) AND PurchaseTime < 
DATEADD(DAY, 1, 
CONVERT(DATE, 
GETDATE()))
Explanation:
http://technet.microsoft.com/en-us/libr ary/ms181034.aspx