Question

I have table

        id  year  month  day  
         1  2012    1     1
         2  2012    1     2
         3  2012    1     3
         4  2012    1     4
         5  2012    1     5
         6  2012    1     7
         7  2012    1     8
         8  2012    1     9
         9  2012    1     10
         10 2012    1     11

from the above table i want to generate the following output when count of id reaches the
multiple of 5

          day_start day_end
             1         5   
             5         11 

Answer 1

This will work in SQL Server. Using the row_number rather than the id field value will prevent errors if you delete rows and the sequence of ids is no longer complete.

Note: I’m basing this answer on the fact that you said the “count of id” reaches 5, and not “the value of id”. Which to me means “every 5 records, regardless of the id value”. If that’s not the case, then leave a comment and I’ll remove this answer, since Mark’s will work fine.

select case when rownumber = 5 then 1 else rownumber - 5 end as day_start, day_end
from
(
    select row_number() over (order by id) as RowNumber, [day] as day_end
    from table1
) t
where rownumber % 5 = 0