updating only date part from datetime in sql server 2000

I have data in the table like the following.

col1                   col2                   col3
----------------开发者_StackOverflow中文版----------------------------------------
6/5/2010 18:05:00   6/2/2010 10:05:00         Null
6/8/2010 15:05:00   6/3/2010 10:45:00       6/5/2010 11:05:00 
6/3/2010 15:05:00   Null                    6/7/2010 12:05:00 
6/1/2010 15:05:00   6/3/2010 10:45:00       6/1/2010 14:05:00 

what my requirement is I want to update the date of there columns with single date without disturbing the time. say for example I want to update the table data with 6/1/2010 where the field data is not null. please let me know the query for updating the table data.

thanks & regards,

murali

I think this should work for you.

create table #t
(
col1 datetime
)

Insert Into #t 
values ('2010-06-01 10:00:00')

Insert Into #t 
values ('2010-06-06 11:00:00')

Insert Into #t 
values ('2010-05-24 12:40:00')

Insert Into #t 
values ('2010-05-07 13:00:00')

Insert Into #t 
values (Null)

declare @newDate datetime

set @newDate = '2010-07-01'

update #t
Set col1 = DateAdd(day, DateDiff(day, col1, @newDate), Col1)
Where Col1 is not null


select * From #t

drop table #t

You may need to do it via SELECT statement as you dont need to run UPDATE statement each time new data are added to the table