Question

This is what I am trying to achieve:

1. define a cursor

2. which return me list of rows

3. use the rows to do some modify tables

4. repeat 2 and 3 until cursor returns no result.

this is what I have done so far

DECLARE
  CURSOR c1 IS
    [My SQL HERE];

BEGIN

   FOR r1 in c1 LOOP
   [modify tables]

END; 

question is where do I put the while? I would do it before the for loop. but whats the syntax in pl/sql to describe c1 has result?

Note after c1 fullly finish I need to rerun the cursor code. Make another iteration . Because the result will be different. That’s why I needed the while

Answer 1

The answer is combine ‘while’ with ‘for ‘. Obviously only if you want to run the cursor multiple times, because you are update/alter something inside the cursor, and the condition changed, thus you need to re-run the cursor again.

here is the basic structure:

 DECLARE
  CURSOR c1 IS
    [My SQL HERE];

BEGIN

   WHILE CONDITION LOOP

   FOR r1 in c1 LOOP
   [modify tables]
   END LOOP; -- for loop

   [Check The Condition]

   END LOOP; -- while loop

 END; 

e.g

  DECLARE

  counts NUMBER := -1;
  CURSOR c1 IS
    [Statement Here];

BEGIN

   WHILE count != 0 LOOP

   FOR r1 in c1 LOOP
   [modify tables]
   END LOOP; -- for loop

   SELECT count(*) ...... INTO counts

   END LOOP; -- while loop

END;