Question

Just wondering if anyone can help me with this. I would like to round the SQL datetime to the nearest 5 seconds

For example the dates on the left should give me the following result on the right.

• 1900-01-01 14:08:20.000 -> 1900-01-01 14:08:20.000
• 1900-01-01 14:08:21.000 -> 1900-01-01 14:08:20.000
• 1900-01-01 14:08:22.000 -> 1900-01-01 14:08:20.000
• 1900-01-01 14:08:23.000 -> 1900-01-01 14:08:25.000
• 1900-01-01 14:08:24.000 -> 1900-01-01 14:08:25.000
• 1900-01-01 14:08:25.000 -> 1900-01-01 14:08:25.000

I have seen a similar solution for minute intervals and I have tried to apply it to seconds but it doesn’t give the ideal result.

declare @DT datetime

set @DT = convert(datetime,'14:08:20')
select dateadd(s,(datepart(s,dateadd(s,1,@DT))/5)*5,
    dateadd(mi,datediff(mi,0,dateadd(s,1,@DT)),0))

However, 1900-01-01 14:08:23.000 gives me 1900-01-01 14:08:20.000, which is not correct.

Any help is appreciated.

Answer 1

With some usage of DATEPART() and ROUND(), you can achieve this

Query

declare @t table (dt datetime);

insert @t 
select
'1900-01-01 14:08:20.000' union all select
'1900-01-01 14:08:21.000' union all select
'1900-01-01 14:08:22.000' union all select
'1900-01-01 14:08:23.000' union all select
'1900-01-01 14:08:24.000' union all select
'1900-01-01 14:08:25.000';

select dt, 
       dateadd(second, round(datepart(second,dt)*2,-1) / 2-datepart(second,dt), dt)
from   @t
order by dt;

Results:

dt                      rounded
----------------------- -----------------------
1900-01-01 14:08:20.000 1900-01-01 14:08:20.000
1900-01-01 14:08:21.000 1900-01-01 14:08:20.000
1900-01-01 14:08:22.000 1900-01-01 14:08:20.000
1900-01-01 14:08:23.000 1900-01-01 14:08:25.000
1900-01-01 14:08:24.000 1900-01-01 14:08:25.000
1900-01-01 14:08:25.000 1900-01-01 14:08:25.000