Question

I’m using SQL Developer for Oracle 11g..

I need to be able to loop through a set of dates,
check to see if the date above or below is = or < or >..

Then assign a trip number that is the same as the one its = to or
assign a new trip number and then begin a new trip and check again
the next date to see if its = or < or > than the current date..

I think in order to do this I need to use the pl/sql cursor for loop..
I’ve tried to figure it out but its not making much sense to me..

For example, I want the end result to be something like this..

ROWID     DATE        TRIP
  1         1-Jan-12    1
  2         2-Jan-12    2
  3         2-Jan-12    2
  4         3-Jan-12    3
  5         4-Jan-12    4
  6         1-Jan-12    1
  7         4-Jan-12    4

Thanks in advance for your help.
Alex

Answer 1

You don’t need to loop at all! All you need is the analytic function dense_rank:

select t.*,
       dense_rank() over (order by startdate) as trip
from t