I've had to link on a previous row in the past. I've just used self joins, i.e. joining a table on itself. In the join clause, I just put my criteria. For example:

select t1.price as 'oldprice', t2.price as 'newprice' from table1 t1 join table1 t2 on t1.colnum +1= t2.colnum

Is there anything wrong with doing that? Is it less efficient or buggy?

Thanks,

Seth