variable usage in nested cursors - mysql

Question

I have a stored procedure snippet like this
CREATE DEFINER=`root`#`%` PROCEDURE `new_procedure`()
BEGIN
DECLARE c_id varchar(100) DEFAULT "";
DECLARE cursor1 CURSOR for select id from t1 where name like 's%';
OPEN cursor1;
get_t1: LOOP
FETCH cursor1 into c_id;
p:begin
declare cursor2 cursor for select id from t2 where cl_id=c_id;
open cursor2;
get_t2: loop
fetch project_cursor into p_id;
// perform some tasks
t:begin
declare cursor3 cursor for select id from t3 where pr_id=p_id;
open cursor3;
get_t3:loop
fetch cursor3 into t_id;
IF v_finished = 1 THEN
LEAVE get_t3;
END IF;
//perform some tasks
close cursor3;
select p_id;
end t;
end loop t2;
end p;
END LOOP t1;
END
here select statement is not displaying any data
when i write select under cursor 3 it is working.
did i made any mistake? anything I missed

Answer 1

Some basic logic has been added in your SP, Try it whether this is what you are expecting.
CREATE DEFINER=`root`#`%` PROCEDURE `new_procedure`()
BEGIN
DECLARE c_id VARCHAR(100) DEFAULT "";
DECLARE done1 BOOLEAN DEFAULT FALSE;
DECLARE cursor1 CURSOR FOR SELECT id FROM t1 WHERE name LIKE 's%';
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done1=TRUE;
OPEN cursor1;
GET_T1: LOOP
FETCH cursor1 INTO c_id;
IF done1 THEN
LEAVE GET_T1;
END IF;
P:BEGIN
DECLARE p_id INT ; -- check which data types suits you, might be int
DECLARE done2 BOOLEAN DEFAULT FALSE;
DECLARE cursor2 CURSOR FOR SELECT id FROM t2 WHERE cl_id=c_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done2=TRUE;
OPEN cursor2;
GET_T2: LOOP
FETCH cursor2 INTO p_id;
IF done2 THEN
LEAVE GET_T2;
END IF;
/* perform some task */
T:BEGIN
DECLARE t_id INT ; -- check which data types suits you, might be int
DECLARE done3 BOOLEAN DEFAULT FALSE;
DECLARE cursor3 CURSOR FOR SELECT id FROM t3 WHERE pr_id=p_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done3=TRUE;
OPEN cursor3;
GET_T3:LOOP
FETCH cursor3 INTO t_id;
IF done3 THEN
LEAVE GET_T3;
END IF;
/* perform some tasks */
#select p_id; -- don't know what you are doing with this
END LOOP GET_T3;
CLOSE cursor3;
SET done3=FALSE;
END T;
END LOOP GET_T2;
CLOSE cursor2;
SET done2= FALSE;
END P;
END LOOP GET_T1;
CLOSE cursor1;
SET done1= FALSE;
END