Question

I have a stored procedure :-

CREATE procedure St_Proc_GetTimeEntryID            
@userID int,            
@timeEntryID int output            
as begin             
    set nocount on;      
    SET @timeEntryID=0      
    DECLARE @TEMP INT       
    SET @TEMP=0        
    SELECT @TEMP=ProductionTimeEntryID            
    FROM    production            
    WHERE   ProductionTimeEntryID =             
        (SELECT MAX(ProductionTimeEntryID)             
            FROM production            
            where UserID=@userID             
            and (CalendarDate = (select GETDATE()))            
            and IsTaskCompleted=1 )      
            BEGIN      
                SET @timeEntryID=@TEMP      
            END      
END

Here CalendarDate is column which containing Date As 06/26/201212:00PM format .
I want to compare the date part only with system date part (06/26/2012 = 06/26/2012) in my subquery which is

(SELECT MAX(ProductionTimeEntryID)             
            FROM production            
            where UserID=@userID 
            and (CalendarDate = (select GETDATE()))            
            and IsTaskCompleted=1 )

Please guide me what modification i ll do to get the result.

Answer 1

The most efficient method (meaning fully able to utilize an index on CalendarDate, if one exists) is going to be, on SQL Server 2000/2005:

DECLARE @today SMALLDATETIME;
SET @today = DATEDIFF(DAY, 0, CURRENT_TIMESTAMP);

...
WHERE CalendarDate >= @today
AND CalendarDate < DATEADD(DAY, 1, @today);

If using SQL Server 2008+:

DECLARE @today DATE = CURRENT_TIMESTAMP;
...
WHERE CalendarDate >= @today
AND CalendarDate < DATEADD(DAY, 1, @today);

You can also use a direct cast in SQL Server 2008+, but I’m not 100% sure this is guaranteed to use an index on CalendarDate in all scenarios:

WHERE CONVERT(DATE, CalendarDate) = CONVERT(DATE, CURRENT_TIMESTAMP);

Because this casting does not work with other date/time data types, for consistency I much prefer the open-ended range technique, and definitely do not condone most of the scenarios where you perform implicit or explicit conversions on the column (since this usually means an index won’t be used). I’ve ranted about this and several other date/time atrocities plenty at the following blog posts:

• What do BETWEEN and the devil have in common?

• Bad habits to kick : mis-handling date / range queries