MySQL Cursor Error Unknown Variable - mysql

Question

I created a store procedure to do some insertions, fetch the records of a table and insert it into another table. For that I used cursor (my first use of cursor).
My script below:
CREATE DEFINER=`root`#`localhost` PROCEDURE `tenant_creation`(
IN admin_id int, tenant_name varchar(50),tenant_url varchar(50),
tenant_email varchar(50),tenant_phone varchar(50),first_name varchar(50),
last_name varchar(50),plan_id varchar(50),IN is_available tinyint
)
BEGIN
DECLARE exit handler for sqlexception
BEGIN
ROLLBACK;
END;
DECLARE exit handler for sqlwarning
BEGIN
ROLLBACK;
END;
BEGIN
START TRANSACTION;
#insert Tenant details
Insert into tenant(admin_id,tenant_name,tenant_url,tenant_email,tenant_phone,first_name,last_name,plan_id, is_available)
values(admin_id,tenant_name,tenant_url,tenant_email,tenant_phone,first_name,last_name,plan_id,is_available);
SET #tenant_id = LAST_INSERT_ID();
#create Administrator Group
Insert into user_group(tenant_id,user_group_name,description)
values(#tenant_id,"Administrator","Default Administrator's Group");
SET #group_id = LAST_INSERT_ID();
#Create Default Tenan Admin User
Insert into users(tenant_id,username,`password`,firstname,lastname,email)
values(#tenant_id,"Administrator","$2y$10$AxTjqOxYk6atjDSO2Q4iQOprSvYMnR/jAboqfDYkvC1IG43Rwknw6","Default","Default",tenant_email);
#Attach the user to the group
Set #user_id = LAST_INSERT_ID();
Insert into user_group_relationship(tenant_id,user_group_id,user_id)
values(#tenant_id,#group_id,#user_id);
#create Admin profile
insert into profile(tenant_id,profile_name,description)
values(#tenant_id,"Administrator","Administrator Profile");
#Attach the Admin group to the profile
Set #profile_id = LAST_INSERT_ID();
Insert into profile_group_relationship(tenant_id,group_id,profile_id)
values(#tenant_id,#group_id,#profile_id);
END;
BEGIN
#bind the profile to the available screens
#1 fetch all the modules in system
DECLARE cur CURSOR FOR Select system_screen.screen_id,system_screen.screen_name,module_screen_relationship.module_id
from system_screen
join module_screen_relationship
on module_screen_relationship.screen_id = system_screen.screen_id;
begin
DECLARE done INT DEFAULT 0;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cur;
read_loop: LOOP
#Fetch one record from CURSOR and set to some variable(If not found then done will be set to 1 by continue handler)
FETCH cur INTO c_screen_id,c_screen_name,c_module_id;
#If done set to 1 then exit the loop else continue
IF done THEN
LEAVE read_loop;
END IF;
Insert into profile_screen_relationship(tenant_id,profile_id,screen_id,module_id,access_level)
values(#tenant_id,#profile_id,c_screen_id,c_module_id,4);
END LOOP read_loop;
#Closing the cursor
CLOSE cur;
End;
COMMIT;
END;
END
but I only got "Error 1327: Undeclared variable: c_screen_id".
What do you think I am doing wrong?

Answer 1

I believe that you have to declare the variables at the beggining as the official documentation shows:
http://dev.mysql.com/doc/refman/5.7/en/cursors.html
DECLARE a CHAR(16);
DECLARE b, c INT;
....
FETCH cur1 INTO a, b;
FETCH cur2 INTO c;