Thanks for looking and helping!
I've written this very simple cursor, but for some reason it does't want to work:
drop table if exists t1;
drop procedure if exists simple_loop;
create temporary table values ('chris'),('peter'),('brian'),('stewie'),('meg');
create procedure simple_loop()
begin
declare finished int default false;
declare n varchar(45);
declare c cursor for select name from t1;
declare continue handler for not found set finished = true;
open c;
c_loop: loop
fetch c into n;
--if finished then leave c_loop;
select n;
end loop;
end
As you can see, I have commented out the line that says to leave the loop when the results are done. This is because the whole procedure script won't execute.
If the line is there, it will not complain about that line causing an issue, but the end:
...the right syntac to use near 'loop;end' ErrorCode: 1064
I do not know why that is. The MySQL documentation does't seem to be much help. If I also add the line 'close c;' it won't work either, but pointing out the whole end as an error.
Any pointers much appreciated.
MySQL version is 5.5 on Ubuntu.
Thanks, Chris
this seems to be fixed! I forgot to terminate that if statement:
drop table if exists t1;
drop procedure if exists simple_loop;
create temporary table values ('chris'),('peter'),('brian'),('stewie'),('meg');
create procedure simple_loop()begin
declare finished int default false;
declare n varchar(45);
declare c cursor for select name from t1;
declare continue handler for not found set finished = true;
open c;
c_loop: loop
fetch c into n;
if finished then leave c_loop; end if;
select n;
end loop;
end
look at the previously commented out line:
if finished then leave c_loop; END IF;
Related
It's the first time I use cursors and im having issues with the variable 'done'. This variable handles whether the loop iterates over the cursosr or not. When the trigger its executed, the following error happens:
ERROR 1193 (HY000): Unknown system variable 'done'
As far as i see in the mysql cursor documentation, the 'done' variable declaration is correct. Anyone sees the problem?
The trigger:
delimiter //
CREATE TRIGGER `prestamo_positivo` AFTER UPDATE ON `prestamo`
FOR EACH ROW BEGIN
DECLARE aux VARCHAR(10);
DECLARE aux2 CHAR(10);
DECLARE c1 CURSOR FOR SELECT id_cliente FROM PRESTATARIO;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
SET aux=(SELECT A.id_cliente FROM PRESTATARIO A, PRESTAMO B WHERE A.numero_prestamo=OLD.numero);
IF(NEW.cantidad = 0) THEN
DELETE FROM `prestamo` WHERE numero=OLD.numero;
OPEN c1;
c1_loop: LOOP
fletch c1 into aux2;
IF done THEN LEAVE c1_loop; END IF;
IF(aux = aux2) THEN
INSERT INTO `mensaje`(mensaje, id_usuario) VALUES ("Renegociar prestamos del cliente",aux);
END IF;
END LOOP c1_loop;
CLOSE c1;
END IF;
END; //
If you check the sample code you linked in the question, you can see that done variable is explicitly declared before the continue handler, so you need to do the same. The below excerpt is from the sample code from the link you specified:
DECLARE done INT DEFAULT FALSE; //<= declare done variable here
DECLARE a CHAR(16);
DECLARE b, c INT;
DECLARE cur1 CURSOR FOR SELECT id,data FROM test.t1;
DECLARE cur2 CURSOR FOR SELECT i FROM test.t2;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
Also, as P.Salmon has already remarked, you cannot modify the table the trigger is declared on, therefore
DELETE FROM `prestamo` WHERE numero=OLD.numero;
line will fail with error 1442.
I'm working on a 8.0.15 Mysql on which I have several stored procedures.
The "master" call the others, and every procedure may (or may not) call other procedures themselves
My goal is to have a "tree" of the procedures, to document the order on which they are called.
Any ideas on how to do so? I was thinking to query information_schema.ROUTINES tables, extract only the various Call with some regex to have only the "bone" of my procedures, something like:
MAIN_PROCEDURE
CALL PCD2();
CALL PCD3();
END;
PCD2
CALL PCD4();
END;
then, recursively do it in order to know that PCD4 is called inside PCD2.
I'm stuck on the first part, then the recursive query should be quite easy
Any help? Of course any other method is fine!
Thanks in advance
would like to know if there is an automatic way to deal with unbalanced data. Let's say it is a binary classification problem and I want to use cross-validation, for example kfolds.
Do you know if there is any cross-validation technique that does not only randomly shuffle the data, but also tries to "balance" the labels in the train set so it is 50%-50%?
That would help to not get high accuracy scores, just because the model has higher changes to learn more points from a particular class.
Try this code. Put your database name in "MyDataBase".
CREATE DEFINER=root#localhost PROCEDURE dependencias()
NO SQL;
BLOCK1:BEGIN
DECLARE bas, c1 VARCHAR(50);
DECLARE fin int DEFAULT FALSE;
DECLARE cur1 CURSOR FOR SELECT specific_name from information_schema.routines where routine_schema= bas;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET fin = TRUE;
SET bas='MyDataBase';
DROP TABLE IF EXISTS dependencias;
CREATE TABLE dependencias (a varchar(50), b varchar(50));
OPEN cur1;
rulo1: LOOP
FETCH cur1 INTO c1;
IF fin THEN
LEAVE rulo1;
END IF;
BLOCK2: BEGIN
DECLARE can int;
DECLARE c2,cad varchar(50);
DECLARE fin int DEFAULT FALSE;
DECLARE cur2 CURSOR FOR SELECT specific_name from information_schema.routines where routine_schema= bas;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET fin = TRUE;
OPEN cur2;
rulo2: LOOP
FETCH cur2 INTO c2;
IF fin THEN
LEAVE rulo2;
END IF;
SET cad=CONCAT ('%',c2,'(%');
SET can=(SELECT COUNT(*) FROM information_schema.routines WHERE Routine_Name = c1 AND routines.routine_definition LIKE cad AND Routine_Schema = bas);
IF c1!=c2 AND can>0 THEN
INSERT INTO `dependencias` values (c1,c2);
END IF;
END LOOP rulo2;
CLOSE cur2;
END BLOCK2;
END LOOP rulo1;
CLOSE cur1;
END BLOCK1
I think I'm narrowing in on my issue. I have a loop that is only firing once:
DELIMITER $$
DROP PROCEDURE IF EXISTS `thread_updates` $$
CREATE PROCEDURE `thread_updates`()
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE my_curr_id INT DEFAULT NULL;
-- DECLARE other vars
DECLARE fixer_cursor CURSOR FOR
SELECT DISTINCT(id)
FROM log
WHERE date >= '2018-01-01';
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN fixer_cursor;
REPEAT
FETCH fixer_cursor INTO my_curr_id;
IF NOT done THEN
SELECT data FROM table WHERE id = my_curr_id; -- This may not exist
-- Do other stuff with 'data' or NULL from above
END IF;
UNTIL done END REPEAT;
CLOSE fixer_cursor;
END $$
DELIMITER ;
I think the issue may be that inside the IF NOT done THEN loop, I have a few select statements that may be trying to select results that don't exist (not found).
This is fine (for me) as the logic continues along using NULL values in those spots, but I suspect that my CONTINUE HANDLER FOR NOT FOUND is catching the NOT FOUND warning that these selects throw inside the loop and are thus stopping the entire loop prematurely.
How can I listen for NOT FOUND warning on my cursor only?
Or, how can I suppress the NOT FOUND warning in my MAYBE FOUND select statements inside my loop so my loop continues?
I think I have solved the issue by implementing a counter in a loop rather than relying on the NOT FOUND handler:
DELIMITER $$
DROP PROCEDURE IF EXISTS `thread_updates` $$
CREATE PROCEDURE `thread_updates`()
BEGIN
DECLARE my_total INT DEFAULT NULL; -- Declare total
DECLARE my_counter INT DEFAULT 0; -- Declare counter starting at 0
DECLARE my_curr_id INT DEFAULT NULL;
-- DECLARE other vars
DECLARE fixer_cursor CURSOR FOR
SELECT DISTINCT(id)
FROM log
WHERE date >= '2018-01-01';
OPEN fixer_cursor;
SELECT FOUND_ROWS() INTO my_total; -- Get total number of rows
my_fixerloop: LOOP
FETCH fixer_cursor INTO my_curr_id;
IF my_counter >= my_total THEN -- Compare counter to total
CLOSE fixer_cursor;
LEAVE my_fixerloop;
END IF;
SET my_counter = my_counter + 1; -- Increment by one for each record
SELECT data FROM table WHERE id = my_curr_id; -- This may not exist
-- Do other stuff with 'data' or NULL from above
END LOOP;
END $$
DELIMITER ;
I am working on a MySQL procedure that creates a summary of one of my tables. The procedure retrieves a dataset and loops through it using a cursor. For each iteration of the loop, the procedure updates another table. The problem I'm having is the loop ends after a single iteration, event though I know that the query I'm running retrieves more than one row.
BEGIN
# Variable declaration section omitted for brevity
DECLARE cur CURSOR FOR SELECT
t.result_id,
t.athlete_id, t.`first`, t.middle, `last`, t.pref, t.birth,t.uss,
t.club_id,t.code,t.club_name,
t.meet_name,t.meet_id,t.`start`,t.`end`,
MIN(t.time) as time,t.age,t.type
FROM sometable t GROUP BY club_id ORDER BY time asc,t.start desc,club_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN cur;
read_loop: LOOP
FETCH cur INTO result_id,athlete_id, first_name, middle, last_name, pref, birth,uss,
club_id,club_code,club_name,
meet_name,meet_id,start_date,end_date,
result_time,age,type;
IF done=1 THEN
LEAVE read_loop;
END IF;
SET last_time = result_time;
INSERT INTO toptimes(`result_id`,`club_id`,`agegroup`,`sex`,`distance`,`course`,`stroke`,`data`,`published`)
VALUES(result_id,club_id,AgeGroupID,sex,distance,course,stroke,json,0);
END LOOP read_loop;
CLOSE cur;
END
I'm not clear what the problem is. When I run the select query manually, I get back several rows. Is there a problem running an insert statement inside the loop?
Your code chunk looks good to me.
How do you know that it's running only one iteration (i'm not seeing any
print or select statement for debug purpose)?
Are you getting any error while executing the stored procedure?
I tried to replicate the similar code with "sakila" database (mysql sample db). It's working perfectly. Please check this sql code sample, if it helps you.
DROP PROCEDURE IF EXISTS usp_select_dummy_data ;
DELIMITER $$
CREATE DEFINER=`root`#`localhost` PROCEDURE usp_select_dummy_data()
BEGIN
-- Declare your variables
Declare _var_actor_id int default 0;
DECLARE _var_film_id int default 0;
-- Declare variable used for cursor and loop control
DECLARE done int;
DECLARE loop_counter INT DEFAULT 0;
-- Declare the cursor
DECLARE cur CURSOR FOR
SELECT
actor_id, film_id
FROM film_actor;
-- Declare handlers
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
-- Open the cursor
OPEN cur ;
-- Start the loop
read_loop: LOOP
FETCH cur
INTO _var_actor_id, _var_film_id ;
-- break out of the loop if
-- 1. if there is no rows or
-- 2. we've processed them all
IF done = 1 THEN
CLOSE cur ;
LEAVE read_loop ;
END IF;
-- Count the number of times looped
SET loop_counter = loop_counter + 1 ;
END LOOP read_loop ;
-- print the loop count
select loop_counter;
END
I have written a stored proc in mysql when i am running it through hopper it is working fine but when i am trying to run it from mysql workbench or java it is not returning any result and also not showing any exception
I will request you to please help me on this
-- --------------------------------------------------------------------------------
-- Routine DDL
-- Note: comments before and after the routine body will not be stored by the server
-- --------------------------------------------------------------------------------
DELIMITER $$
CREATE DEFINER=`root`#`localhost` PROCEDURE `issueitem`()
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE inventoryids INT DEFAULT 0;
DECLARE batch varchar(39);
DECLARE resultstr varchar(3000) DEFAULT '';
DECLARE exp DATE;
DECLARE mfgdate DATE;
DECLARE availableunit INT;
DECLARE quantity INT DEFAULT 100;
DECLARE oldest_date DATETIME;
DECLARE cur_count INT;
DECLARE que_size INT DEFAULT 0;
DECLARE curs CURSOR FOR SELECT inventoryid,batch,exp,availableunit FROM aashramdata.inventory where itemid=1 ORDER BY exp ASC;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN curs;
SET cur_count=quantity;
read_loop: LOOP
FETCH curs INTO inventoryids,batch,exp,availableunit;
IF done THEN
LEAVE read_loop;
END IF;
SET que_size = que_size + availableunit;
IF cur_count >= availableunit THEN
set cur_count=cur_count-availableunit;
set resultstr=CONCAT(resultstr,batch,' - ',exp,' - ',availableunit,' - ');
update aashramdata.inventory set `availableunit`=0 where inventoryid=inventoryids;
END IF;
IF cur_count < availableunit THEN
update aashramdata.inventory set `availableunit`=availableunit-cur_count where inventoryid=inventoryids;
set resultstr=CONCAT(resultstr,batch,' - ',exp,' - ',availableunit-cur_count,' - ');
set cur_count=0;
END IF;
IF que_size >= quantity then
LEAVE read_loop;
END IF;
END LOOP;
CLOSE curs;
select resultstr;
END
Since the procedure is apparently syntactically valid, it's impossible to answer what the problem might be, without some knowledge of the data.
The easiest way to debug a stored procedure is by peppering it with unbounded SELECT statements (that is, selects that are not part of a subquery and not part of an INSERT ... SELECT or SELECT ... INTO) and then running it from the MySQL command line client, which handles multiple result sets from stored procedures much more gracefully than most graphical clients.
For example:
...
SET cur_count=quantity;
SELECT cur_count; -- add this
read_loop: LOOP
FETCH curs INTO inventoryids,batch,exp,availableunit;
SELECT inventoryids,batch,exp,availableunit; -- add this
SELECT done; -- add this
IF done THEN
...
When run from the command line client...
mysql> CALL issueitem();
...output will start rolling out of the console at you, showing you the internal values the procedure is encountering as it iterates the loop.
This, or other SELECT statements like this added elsewhere, will expose the internal variables and this should help you find the problem. You'll need to remove them before you call the procedure from code or even the GUI since the GUI may not handle them well -- it may start opening new tabs or splitting panes or just ignoring everything after the first SELECT.
Note that the last iteration of the loop, you may see the values from the previous iteration repeated since the failed read from the cursor may not reset the variables, but "done" will also transition from 0 to 1 indicating that the cursor has run out of rows and fired the CONTINUE HANDLER, so those values won't actually have been processed twice.