T-SQL to trim a datetime to the nearest date?

问题:

Duplicate of What's the BEST way to remove the time portion of a datetime value (SQL Server)?

I have a column that tracks when things are created using a datetime, but I'd like to generate a report that groups them by day, so I need a way of nulling out the time component of a datetime column.

How do I do this?

回答1:

One way is to change getdate() to your column name,

select dateadd(dd, datediff(dd, 0, getdate())+0, 0)

回答2:

Why not convert straight to date:

select convert(date, getdate())

This truncates days, not rounds. To round Days do this:

select convert(date, getdate() + 0.5)

回答3:

Here's another solution:

SELECT CAST( FLOOR( CAST( GETDATE() AS float) ) AS smalldatetime)

回答4:

convert(varchar, the date field/value/etc, 101)

This is the simplest way to get the date from a datetime.

回答5:

Yes. There are many formats to choose from so I'll link it instead.

http://library.cirr.com/Microsoft/SQL-Server-v7/html/ca-co_1.htm

If you wish to zero out the time like your post implies, you can try this:

select cast(convert(varchar, getdate(), 101) as datetime)

回答6:

declare @CurrentDate datetime
set @CurrentDate = dateadd(dd, datediff(dd, 0, getdate()), 0)

--or--

select dateadd(dd, datediff(dd, 0, MyDateColumn), 0) as DateOnly
from tblX

回答7:

In my searches I came across the following solution, it strips time out of UTC time only, but I found it interesting, so I thought someone else would too:

FUNCTION TrimDate(@dt AS DATETIME) RETURNS DATETIME
BEGIN
    RETURN CAST(CAST((@dt - 0.500000038580247) AS INT) AS DATETIME) 
END

I would presume that it runs quickly since all it's doing is rounding and casting.

回答8:

I simply do cast(getdate() as date)