this is tabel whose time column need to be sumup..
this is the result..
ans this is the sql script.
declare @tmpTable Table(AH varchar(20))
insert into @tmpTable values('7:30')
insert into @tmpTable values('2:30')
select * from @tmpTable
declare @Minutes as float
declare @Hours as float
declare @HoursFromMunite as Float
select @Hours=sum(cast (substring(AH,0,CHARINDEX(':',AH)) as int)),@Minutes= sum(cast( substring(AH,CHARINDEX(':',AH)+1,len(AH)) as int)) from @tmpTable
set @Minutes= ((@Minutes/60)-@HoursFromMunite)*60
select cast(@Hours as varchar(5))+':'+cast(@Minutes as varchar(5)) as Total