previous row oracle in cursor

Question

I'm here because i could not finde anywhere else if there is a way to return the previous value in a loop (Cursor) to compare with the current value, for instance..

Cursor.Value = Cursor-1.Value;

It's bacause i have several contract numbers that i need to send by mail to the Business sector, but, in order to resume all the rows i want to compare if the current contract number are the same as the last contract number and validate it to dont send duplicated contract numbers.

Exemple of Record that i to skip in order to send no duplicate "Order Numbers": (Order_Number is my Key, not a sequencial numeric id):

cCursor.Value = cCursor-1.Value

cCursor.(111) = cCursor-1.(111)

Exemple of Record that i want to save in order to send as a processed "Order Number": (Order_Number is my Key, not a sequencial numeric id):

cCursor.Value = cCursor-1.Value

cCursor.(132) = cCursor-1.(111)

My Regards.

Answer 1

You cant reference backwards. Th easiest alternative is to store the key value (contract_id) in a variable and have logic like:

DECLARE
   CURSOR c1 IS .....;
   vLastContractID  NUMBER := 0;
BEGIN
   FOR r1 IN c1 LOOP
      IF vLastContractID != r1.CONTRACT_ID THEN
         -- do something
         vLastContractID := r1.CONTRACT_ID;
      END IF;
   END LOOP;
END;