Update date only in SQL Server [duplicate] - sql

Question

This question already has an answer here:
T-SQL: How to update just date part of datetime field?
(1 answer)
Closed 9 years ago.
I have this row in my database table with a value of 1/5/2013 5:50:00 PM, and I want to update only the date part. Time should be same without any change, need to change only the date in this record.
I have tried the update statement but it change the time as well..but I can do a
UPDATE table1
SET date = '1/10/2013 5:50:00 PM'
WHERE id =1
This not what I'm looking for, different id's have different times, so just need to update the date keeping the time in that record same.
Please give feedback.
Thank you

Answer 1

You can do it this way if you're using SQL Server 2008 or higher
UPDATE table1
SET [date] = cast('1/10/2013' as datetime) + cast(cast([date] as time) as datetime)
WHERE id =1
If you're using SQL Server 2005 or below, you there's no time data type, so you have to do:
UPDATE table1
SET [date] = cast('1/10/2013' as datetime) + ([date] - DATEADD(dd, 0, DATEDIFF(dd, 0, [date])))
WHERE id =1

Answer 2

UPDATE table1
SET date = DATEADD(dd,5,date)-- 5 is the number of days
FROM table1
WHERE id =1

Answer 3

Not the most elegant, but should work. Idea is to extract hours,minutes and seconds from target row and hard code other parts.
update table1 set date = DATEADD(second, DATEPART(second, date), DATEADD(minute, DATEPART(minute, date), DATEADD(hour, DATEPART(hour,date), '2013-01-10')));

Answer 4

Though a bit hackish in appearance, this will do the trick if you ONLY want to change the date part with an arbitary value, and not touch the time part at all:
update table1 set date= '06-dec-2013 ' + cast(datepart(HOUR,date) as varchar(2)) + ':' +
cast(datepart(MINUTE,date) as varchar(2)) + ':' +
cast(DATEPART(SECOND, date) as varchar(2)) + ' ' +
CASE WHEN DATEPART(HOUR, date) < 12 THEN 'AM' ELSE 'PM' END as datetime
where id=1
Replace '06-dec-2013' with the date value you want to replace with.

Answer 5

create table t
(
col1 datetime
)
Insert Into t
values ('1/5/2013 5:50:00 PM')
declare #newDate datetime
set #newDate = '1/10/2013'
update t
Set col1 = convert(datetime,DateAdd(day, DateDiff(day, col1, #newDate), Col1),101)
sql-fiddle demo

Answer 6

Here's the query you want:
declare #TargetDate datetime
set #TargetDate = '20131001' --1st October 2013
update table1 set [date] = DATEADD(day,DATEDIFF(day,[date],#TargetDate),[date])
where id = 1
And here's a complete script to demonstrate it:
declare #t table (dt datetime not null)
insert into #t (dt) values
('2001-01-01T10:53:44.993'),('2012-06-18T15:33:33.333')
declare #TargetDate datetime
set #TargetDate = '20131001' --1st October 2013
update #t set dt = DATEADD(day,DATEDIFF(day,dt,#TargetDate),dt)
select * from #t
Results:
dt
-----------------------
2013-10-01 10:53:44.993
2013-10-01 15:33:33.333
This works by using DATEDIFF to work out how many days different the target date is from each date stored in the table (with appropriate signage) and then adding that difference back onto the date - having the effect of adjusting the date portions of the stored values whilst not affecting the time.