Calculation more than 24 hours in SQL Server 2008 -

i have multiple records workinghours of employee as

02:10:00 03:00:00 12:00:00 12:34:56 

now need add these record , want display in

`hh:mm:ss` 

format. used following query works when sum of record less 24 hours record may greater 24 hours.

select cast(dateadd(millisecond,                 sum(datediff(millisecond, '00:00:00.000'          , cast(workhrs time))), '00:00:00.000') time) total_time tblattend 

i spend more 4 hours on google find solution got no success anymore.

datatype of workinghour column varchar .

the time data type has explicit range 24 hours (see here).

so, think stuck doing conversion yourself. ugly, looks like:

select right('00' + cast(sum(datediff(millisecond, '00:00:00.000', cast(workhrs time))), '00:00:00.000')/(60*60) varchar(255)), 2)             ) +         right('00' + cast((sum(datediff(millisecond, '00:00:00.000', cast(workhrs time))), '00:00:00.000')/60 % 60) varchar(255)), 2) +        right('00' + cast(sum(datediff(millisecond, '00:00:00.000', cast(workhrs time))), '00:00:00.000') % 60 varchar(255)), 2)             )