Question

I’m developing a query, where I need that a certain field of my current line be the result of “the field of my current line” + “the same field of the previous line”. (SQL Server 2008)

How can I do it by using cursors?

Answer 1

Assign the previous line value to a variable:

declare @previosvalue varchar(100) = null;
declare @currentvalue varchar(100);

declare crs cursor for select value from table;
open crs;

fetch next from crs into @currentvalue;
while @@fetch_status = 0
begin
   -- process here. On first row, @previousvalue is NULL
   -- as it should be, since there is no 'previous' of first

   select ... from sometable
   where somecondition = @currentvalue
   and othercondition = @previousvalue;

   set @previousvalue = @currentvalue;
   fetch next from crs into @currentvalue;
end

close crs;
deallocate crs;