DECLARE
var1 varchar2(1);
var2 varchar2(2);

BEGIN

LOOP
 IF :data_block.checkbox = 'Y' THEN
    var1 := :data_block.field1;
    var2 := :data_block.field2;
    LOOP
    IF :SYSTEM.LAST_RECORD='TRUE' THEN
      CREATE_RECORD;
      :data_block.field1 := var1;
      :data_block.field2 := var2;
      NEXT_ITEM;
      EXIT;
    END IF;
    END LOOP;
 END IF;
 EXIT WHEN :SYSTEM.LAST_RECORD='TRUE';
 NEXT_RECORD;
END LOOP;

END;

DECLARE
var1 varchar2(1);
var2 varchar2(2);
pos  NUMBER;
skip BOOLEAN;
BEGIN

FIRST_RECORD;
LOOP
 IF :data_block.checkbox = 'Y' THEN
    var1 := :data_block.field1;
    var2 := :data_block.field2;
    pos  := :SYSTEM.CURSOR_RECORD;
    IF :SYSTEM.LAST_RECORD = 'TRUE' THEN  
	   	 skip := TRUE;
    END IF;
    LAST_RECORD;
    CREATE_RECORD;
    :data_block.field1 := var1;
    :data_block.field2 := var2;
    NEXT_ITEM;
 END IF;
 IF skip != TRUE THEN
   GO_RECORD(pos);
 END IF;
 EXIT WHEN :SYSTEM.LAST_RECORD='TRUE';
 NEXT_RECORD;
END LOOP;
 
END;

declare
  number_of_records number;
  where_am_i number;
  l_deptno   dept.deptno%type;
  l_dname    dept.dname%type;
  l_loc      dept.loc%type;
begin
  go_block('dept');
  
  -- calculate last record number (to know the exit point)
  last_record;
  number_of_records := :system.cursor_record;
  
  -- now duplicate checked records
  first_record;
  loop
    exit when :system.cursor_record = number_of_records + 1;
    if checkbox_checked('dept.cb') then
       -- return to where_am_i + 1 record
       where_am_i := :system.cursor_record;

       -- memorize items in a checked record
       l_deptno := :dept.deptno;
       l_dname  := :dept.dname;
       l_loc    := :dept.loc;
	  	 
       -- create a new record at the bottom 
       last_record;
       create_record;
	  	 
       -- I'll make new values slightly different from the original ones
       :dept.deptno := l_deptno + 1;
       :dept.dname  := 'New ' || l_dname;
       :dept.loc    := 'New ' || l_loc;
	  	 
       -- go back and check another record
       go_record (where_am_i + 1);
    else
       next_record;
    end if;
  end loop;
end;

DECLARE
  number_of_records  NUMBER;
  where_am_i	     NUMBER;
  t1_id_prod_v	     t1.id_prod%TYPE;
BEGIN
  GO_BLOCK('T2');
  CLEAR_BLOCK;
  GO_BLOCK('T1');
	
  last_record;
  number_of_records := :system.cursor_record;
	
  first_record;
	
  LOOP
    EXIT WHEN :system.cursor_record = number_of_records + 1;
		
    IF checkbox_checked('t1.cb') THEN
      where_am_i := :system.cursor_record;
      t1_id_prod_v := :t1.id_prod;
			
      GO_BLOCK('T2');
	
      last_record;
      create_record;
	
	SELECT t2.id_prod, price, price2, price3
	INTO :t2.id_prod, :t2.price, :t2.price2, :t2.price3
	FROM t2
	WHERE t2.id_prod = t1_id_prod_v;
				
      GO_BLOCK('T1');				
				
      GO_RECORD(where_am_i + 1);			
		
    ELSE
      next_record;
    END IF;
		
  END LOOP;

  previous_record; --stop the cursor in the last record
	           --not in the new one
	
END;

LOOP
  <some code here>

  BEGIN
    SELECT t2.id_prod, price, price2, price3
      INTO :t2.id_prod, :t2.price, :t2.price2, :t2.price3
      FROM t2
      WHERE t2.id_prod = t1_id_prod_v;
  EXCEPTION
    WHEN TOO_MANY_ROWS THEN
      -- do *something*; for example, set these values to 0 (zero)
      :t2.id_prod := 0;
      :t2.price   := 0;
      <etc.<
  END;

  <some code here>
END LOOP;

	
SELECT MAX(t2.id_prod), MAX(price), MAX(price2), MAX(price3)
  INTO :t2.id_prod, :t2.price, :t2.price2, :t2.price3
  FROM t2
  WHERE t2.id_prod = t1_id_prod_v;

GO_RECORD(where_am_i + 1);
 IF :system.cursor_record = where_am_i THEN
   EXIT;
 END IF;

EXIT WHEN :system.last_record = 'TRUE';

select empno, ename, sal
from emp
where deptno = 10
  and job = 'MANAGER'

insert into some_other_table (empno, ename, sal)
select empno, ename, sal
from emp
where deptno = 10
  and job = 'MANAGER'