Mysql Cursor Not running nested loop

I created two cursor for loop through each values in outer loop and go through whole inner loop . So i created following nested cursor .but it works when one of my table has one row of data .then i insert more data i first table but the cursor is not working as it should be

 BEGIN
DECLARE done int default false;
DECLARE a,b varchar(20);
DECLARE c,d date;
DECLARE f,j text;
DECLARE cur2 CURSOR FOR SELECT tran_id,tran_date FROM bank_tran where tcheck='NO'; 
DECLARE cur1 CURSOR FOR SELECT stran_id,stran_date,scheck FROM student_tran; 
 DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE; 
 OPEN cur1;
  read_loop: LOOP
    FETCH cur1 INTO a,c,j;
    IF done THEN
         LEAVE read_loop;
      END IF;
    OPEN cur2;
    inside_loop:LOOP
      FETCH cur2 INTO b,d;
      IF done THEN
         LEAVE inside_loop;
      END IF;
      IF (a = b) and (c=d) THEN
        update student_tran set valid='YES',scheck='YES' where stran_id=a;
        update bank_tran set matched_sub_id=a ,tcheck='YES' where tran_id=a;
       CLOSE cur2;
      LEAVE inside_loop;
      ELSE
         ITERATE inside_loop;
      END IF;
    END LOOP inside_loop;

    END LOOP read_loop ;
  CLOSE cur1;
  END

and the structure of my two table that i used in the cursor are

CREATE TABLE IF NOT EXISTS `bank_tran` (
  `tran_id` varchar(20) NOT NULL,
  `tran_date` date NOT NULL,
  `tcheck` text NOT NULL,
  `matched_sub_id` varchar(20) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;


CREATE TABLE IF NOT EXISTS `student_tran` (
  `student_id` varchar(20) NOT NULL,
  `sub_apply_id` varchar(20) NOT NULL,
  `stran_id` varchar(20) NOT NULL,
  `stran_date` date NOT NULL,
  `scheck` text NOT NULL,
  `valid` text NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

And some data for both tables are

    INSERT INTO `bank_tran` (`tran_id`, `tran_date`, `tcheck`, `matched_sub_id`) VALUES

    ('4HZZGl', '2015-02-03', 'NO', ''),
    ('LkvUG5', '2015-02-03', 'NO', ''),
    ('fKbl8H', '2015-02-03', 'NO', ''),
    ('fIS7kg', '2015-02-03', 'NO', ''),
    ('GQqBic', '2015-02-03', 'NO', ''),
    ('ZPU3Yx', '2015-02-03', 'NO', ''),
    ('gKSNz7', '2015-02-03', 'NO', ''),
    ('DeyvKU', '2015-02-03', 'NO', ''),
    ('pKarTd', '2015-02-03', 'NO', ''),
    ('nVbJkW', '2015-02-03', 'NO', ''),
    ('1EuzDN', '2015-02-03', 'NO', ''),
    ('QrIxQD', '2015-02-03', 'NO', ''),
    ('vHtJID', '2015-02-03', 'NO', ''),
    ('cQzbYy', '2015-02-03', 'NO', ''),
    ('MGhWy0', '2015-02-03', 'NO', ''),
    ('6DDsSH', '2015-02-03', 'NO', '');
INSERT INTO `student_tran` (`student_id`, `sub_apply_id`, `stran_id`, `stran_date`, `scheck`, `valid`) VALUES
('', '', '4HZZGl', '2015-02-03', 'NO', ''),
('', '', 'LkvUG5', '2015-02-03', 'NO', ''),
('', '', 'fKbl8H', '2015-02-03', 'NO', ''),
('', '', 'fIS7kg', '2015-02-03', 'NO', ''),
('', '', 'GQqBic', '2015-02-03', 'NO', ''),
('', '', 'ZPU3Yx', '2015-02-03', 'NO', ''),
('', '', 'gKSNz7', '2015-02-03', 'NO', ''),
('', '', 'DeyvKU', '2015-02-03', 'NO', ''),
('', '', 'pKarTd', '2015-02-03', 'NO', ''),
('', '', 'nVbJkW', '2015-02-03', 'NO', ''),
('', '', '1EuzDN', '2015-02-03', 'NO', ''),
('', '', 'QrIxQD', '2015-02-03', 'NO', ''),
('', '', 'vHtJID', '2015-02-03', 'NO', ''),
('', '', 'cQzbYy', '2015-02-03', 'NO', ''),
('', '', 'MGhWy0', '2015-02-03', 'NO', ''),
('', '', '6DDsSH', '2015-02-03', 'NO', '');

what i am doing is that if in student transaction table the stran_id is valid or not if yest then to set corresponding bank_trans 's matched_sub_id to stran_id(for now only to see if its working or not) .i am beginner in pl/sql programming