Handling multiple nested cursors in stored procedure - mysql

How can I use two cursors in the same routine? I am getting "Variable or condition declaration after cursor or handler declaration" error while creating procedure.
I have to use both integer outerDone & innerDone to check whether cursor points to null or not.
I haven't worked on stored-procedure yet. Could anybody sort this problem please. Thanks in advance!!
DELIMITER ##;
create procedure updateStopTimeColumn()
BEGIN
DECLARE outerDone INT DEFAULT 0;
DECLARE vehicle_record CURSOR FOR SELECT `vehicleId` FROM `vehicle`;
DECLARE current_record CURSOR FOR SELECT `id`,`tsTime`,`teTime` FROM `trip` where `vehicleId`=vehId order by `tsTime`;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET outerDone = 1;
DECLARE vehId,tripId CHAR(250);
DECLARE currentTsTime,currentTeTime time;
OPEN vehicle_record;
REPEAT
FETCH vehicle_record INTO vehId;
block2 : BEGIN
DECLARE innerDone INT DEFAULT 0;
DECLARE tempTripId CHAR(250);
DECLARE tempTsTime,tempTeTime time;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET innerDone = 1;
OPEN current_record;
FETCH current_record INTO tempTripId, tempTsTime,tempTeTime;
REPEAT
FETCH current_record INTO tripId,currentTsTime,currentTeTime;
UPDATE trip set stopTime=(currentTeTime-tempTsTime) where id=tempTripId and tempTeTime IS NOT NULL;
SET tempTripId=tempId;
SET tempTsTime=currentTsTime;
SET tempTeTime=currentTeTime;
UNTIL innerDone END REPEAT;
END block2;
CLOSE current_record;
UNTIL outerDone END REPEAT;
CLOSE vehicle_record;
END; ##
DELIMITER;


Have you tried moving the
DECLARE vehId,tripId CHAR(250);
DECLARE currentTsTime,currentTeTime time;
statements to before your cursors?

Related

MySql stored procedure error [ERROR 1338 (42000): Cursor declaration after handler declaration]

I am reading an article on stored procedures and this is the code:
delimiter //
create procedure largest_order(out largest_id int)
begin
declare this_id int;
declare this_amount float;
declare l_amount float default 0.0;
declare l_id int;
declare done int default 0;
declare continue handler for sqlstate '02000' set done = 1;
declare c1 cursor for select orderid, amount from orders;
open c1;
repeat
fetch c1 into this_id, this_amount;
if not done then
if this_amount > l_amount then
set l_amount=this_amount;
set l_id=this_id;
end if;
end if;
until done end repeat;
close c1;
set largest_id=l_id;
end
//
delimiter ;
I am using a simple database named "mydatabase". After running the above code it gives me this error: ERROR 1338 (42000): Cursor declaration after handler declaration
What is wrong and how can I fix it?
This is my first time working with stored procedures.

Per MySql docs:
Cursor declarations must appear before handler declarations and after
variable and condition declarations.
So I updated the code as follows:
delimiter //
create procedure largest_order(out largest_id int)
begin
declare this_id int;
declare this_amount float;
declare l_amount float default 0.0;
declare l_id int;
-- 1. cursor finished/done variable comes first
declare done int default 0;
-- 2. the curser declaration and select
declare c1 cursor for select orderid, amount from orders;
-- 3. the continue handler is defined last
declare continue handler for sqlstate '02000' set done = 1;
open c1;
repeat
fetch c1 into this_id, this_amount;
if not done then
if this_amount > l_amount then
set l_amount=this_amount;
set l_id=this_id;
end if;
end if;
until done end repeat;
close c1;
set largest_id=l_id;
end
//
delimiter ;
And now works fine.

mySQL (stored procedure) cursor infinite loop on last row

I have following code: Problem is on the last row of creature_y loop doesn't end and inserts same values (with increased guid) infinitely.
I tried few ways with changing continue handler but seems it is not that.
DELIMITER $$
DROP PROCEDURE IF EXISTS creature_copy
$$
CREATE PROCEDURE creature_copy ()
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE new_guid INT(10);
-- Creature definition
DECLARE y_guid INT(10);
DECLARE y_id mediumint(8);
DECLARE y_map int(5);
DECLARE y_modelid mediumint(8);
DECLARE y_position_x float(10);
DECLARE y_position_y float(10);
DECLARE y_position_z float(10);
DECLARE y_orientation float(10);
DECLARE y_spawntimesecs INT(10);
DECLARE y_curhealth INT(10);
DECLARE y_curmana INT(10);
DECLARE y_MovementType tinyint(3);
-- waypoints definition
DECLARE w_id INT(10);
DECLARE w_point mediumint(8);
DECLARE w_position_x float(10);
DECLARE w_position_y float(10);
DECLARE w_position_z float(10);
DECLARE w_orientation float(10);
-- Generate creatures map
DECLARE creature_sel CURSOR FOR
SELECT guid,id, map, modelid, position_x, position_y, position_z, orientation, spawntimesecs, curhealth, curmana, MovementType
FROM creature_y;
-- Generate waypoints map
DECLARE waypoint_sel CURSOR FOR
SELECT id, point, position_x, position_y, position_z, orientation
FROM creature_movement
WHERE creature_movement.id = y_guid;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN creature_sel;
-- Cleanup tables before re-running
TRUNCATE creature_t;
TRUNCATE waypoint_data;
-- Set starting guid before loop
SET new_guid = 504115;
creature_loop:LOOP
if done = 1 THEN
-- set done = 0;
CLOSE creature_sel;
LEAVE creature_loop;
end if;
SET new_guid = new_guid + 1;
FETCH creature_sel INTO y_guid, y_id, y_map, y_modelid, y_position_x, y_position_y, y_position_z, y_orientation, y_spawntimesecs, y_curhealth, y_curmana, y_MovementType;
INSERT INTO creature_t(guid, id, map, modelid, position_x, position_y, position_z, orientation, spawntimesecs, curhealth, curmana, MovementType) VALUES(new_guid, y_id, y_map, y_modelid, y_position_x, y_position_y, y_position_z, y_orientation, y_spawntimesecs, y_curhealth, y_curmana, y_MovementType);
OPEN waypoint_sel;
waypoint_loop:LOOP
FETCH waypoint_sel INTO w_id, w_point, w_position_x, w_position_y, w_position_z, w_orientation;
IF done = 1 THEN
SET done = 0;
LEAVE waypoint_loop ;
END IF;
INSERT INTO waypoint_data(id, point, position_x, position_y, position_z, orientation) VALUES (new_guid, w_point, w_position_x, w_position_y, w_position_z, w_orientation);
END LOOP waypoint_loop;
CLOSE waypoint_sel;
END LOOP creature_loop;
CLOSE creature_sel;
END;

I have found solution to this.
To use 2 different continue handlers (to see whether cursor is at end) you need to split code into blocks
BLOCK1: BEGIN
DECLARE done INT DEFAULT 0;
-- First cursor
DECLARE sel CURSOR FOR
SELECT column
FROM table;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN sel;
sel_loop:LOOP
if done = 1 THEN
set done = 0;
CLOSE sel;
LEAVE sel_loop;
end if;
FETCH sel INTO variable1;
-- Do something in loop
-- Start second code-block
BLOCK2: BEGIN
DECLARE done2 INT DEFAULT 0;
-- define second cursor
DECLARE sel2 CURSOR FOR
SELECT column
FROM table
WHERE column = condition;
-- define second handler
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done2 = 1;
-- now you can make second cursor loop and it will finish properly.
OPEN sel2;
sel2_loop:LOOP
FETCH sel2 INTO variable2;
IF done2 = 1 THEN
SET done2 = 0;
LEAVE sel2_loop ;
END IF;
-- do something in second loop
END LOOP waypoint_loop;
CLOSE waypoint_sel;
-- End your code blocks and close first loop / cursor
END BLOCK2;
END LOOP sel_loop;
CLOSE sel;
END BLOCK1

My procedure with cursor doesnt work

I have the next procedure:
BEGIN
DECLARE retribAn INTEGER DEFAULT 0;
DECLARE cPost INTEGER(11);
DECLARE done INT DEFAULT 0;
DECLARE curTipo CURSOR FOR
SELECT RETRIBUCION_ANUAL*1.05 AS RET_AN
FROM EMPLEADOS
WHERE ID_CPOSTAL%2=0;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
OPEN curTipo;
REPEAT
FETCH curTipo INTO retribAn, cPost;
IF NOT done THEN
UPDATE EMPLEADOS
SET RETRIBUCION_ANUAL=retribAn
WHERE ID_CPOSTAL%cPost;
END IF;
UNTIL done END REPEAT;
CLOSE curTipo;
END
when I execute it, sql manager outputs:
Incorrect number of FETCH variables
I do not understand why.
I'm a rookie =D in mysql, and sorry for my English.
Thanks

you are selecting only one column in your cursor query and fetching data into two variables in FETCH
Try this
BEGIN
DECLARE retribAn INTEGER DEFAULT 0;
DECLARE cPost INTEGER(11);
DECLARE done INT DEFAULT 0;
DECLARE curTipo CURSOR FOR
SELECT RETRIBUCION_ANUAL*1.05 AS RET_AN
FROM EMPLEADOS
WHERE ID_CPOSTAL%2=0;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
OPEN curTipo;
REPEAT
FETCH curTipo INTO retribAn; --remove cPost here
IF NOT done THEN
UPDATE EMPLEADOS
SET RETRIBUCION_ANUAL=retribAn
WHERE ID_CPOSTAL%cPost = 0; --change this to value you want to check
END IF;
UNTIL done END REPEAT;
CLOSE curTipo;
END

Mysql syntax error on stored procedure

I run this code as a sql script from command line, and I get "you have an error in your SQL syntax" almost in all lines! Any ideas what is wrong here?
CREATE PROCEDURE updatemandate()
BEGIN
DECLARE _mandate_id BIGINT(20);
DECLARE _has_succesful_payment tinyint(1);
DECLARE done INT DEFAULT 0;
DECLARE cnt INT;
DECLARE mandateCursor CURSOR FOR Select mandate_id, has_succesful_payment From mandates;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN mandateCursor;
allmandates: LOOP
Fetch mandateCursor INTO _mandate_id, _has_succesful_payment;
IF done THEN LEAVE allmandates;
END IF;
Select COUNT(*) FROM payments WHERE mandate_id=_mandate_id AND status='OK' into cnt;
IF cnt>0 THEN
SET _has_succesful_payment=1;
END IF;
END LOOP allmandates;
CLOSE mandateCursor;
END

The ; character is the default delimiter, so when MySQL sees the first ; it thinks you are done. When you create a sproc, you need to declare a different delimiter character, like so:
DELIMITER $$
CREATE PROCEDURE updatemandate()
READS SQL DATA
BEGIN
DECLARE _mandate_id BIGINT(20);
DECLARE _has_succesful_payment tinyint(1);
DECLARE done INT DEFAULT 0;
DECLARE cnt INT;
DECLARE mandateCursor CURSOR FOR Select mandate_id, has_succesful_payment From mandates;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
OPEN mandateCursor;
allmandates: LOOP
Fetch mandateCursor INTO _mandate_id, _has_succesful_payment;
IF done THEN LEAVE allmandates;
END IF;
Select COUNT(*) FROM payment WHERE mandate_id=_mandate_id AND status='OK' into cnt;
IF cnt>0 THEN
SET _has_succesful_payment=1;
END IF;
END LOOP allmandates;
CLOSE mandateCursor;
END$$
DELIMITER ;
Also a good idea to add the READS SQL DATA to the sproc definition in case you need to support binary logging.

Have you tried putting delimiter // before the CREATE statement and change the last line with END //?

How to use many cursors in a single store procedure in MySQL

I want to create a store procedure that has ability to do multi-tasks. Then it got error message below
Error Code: 1338 Cursor declaration after handler declaration
Please look my store procedure
CREATE PROCEDURE `spTest`(OUT v1 VARCHAR(500), OUT v2 VARCHAR(500))
BEGIN
DECLARE _cur_1 CURSOR FOR
SELECT id
FROM tbl_1;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET _cur1Done = 1;
DECLARE _cur_2 CURSOR FOR
SELECT id
FROM tbl_2;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET _cur2Done = 1;
.......

You may only have one continue handler active in a block. Multiple continue handler's get the Duplicate handler declared in same block issue, even if you get the order of declarations correct ( all cursors first, then the handlers later).
You can work around this by creating a block devoted to a cursor's access. You can place these chunks of code in the same parent block, or in nested loops, or wherever.
DELIMITER $$
CREATE PROCEDURE `spTest`(OUT v1 VARCHAR(500), OUT v2 VARCHAR(500))
BEGIN
declare tbl_1_id int;
declare tbl_2_id int;
declare _cur1Done boolean default false;
declare _cur2Done boolean default false;
DECLARE _cur_1 CURSOR FOR SELECT id FROM tbl_1;
DECLARE _cur_2 CURSOR FOR SELECT id FROM tbl_2;
begin -- dedicated block to fetch from cursor 1 and update its flag
declare continue handler for not found set _cur1Done = TRUE;
fetch _cur_1 into tbl_1_id;
end;
begin -- dedicated block to fetch from cursor 2 and update its flag
declare continue handler for not found set _cur2Done = TRUE;
fetch _cur_2 into tbl_2_id;
end;
END $$
DELIMITER ;

In the manual it says
Cursor declarations must appear before handler declarations and after variable and condition declarations.
Also you can not have multiple continue handlers (how should MySQL know which continue handler is related to which cursor? Unfortunately you can't specify that), unless you nest them, for example like this:
DELIMITER $$
CREATE PROCEDURE `spTest`(OUT v1 VARCHAR(500), OUT v2 VARCHAR(500))
BEGIN
BLOCK1:BEGIN
DECLARE variable1 INT;
DECLARE _cur_1 CURSOR FOR SELECT id FROM tbl_1;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET _cur1Done = 1;
LOOP1: LOOP
FETCH _cur_1 INTO variable1;
IF _cur1Done THEN
CLOSE _cur_1;
LEAVE LOOP1;
END IF;
BLOCK2:BEGIN
DECLARE variable2 INT;
DECLARE _cur_2 CURSOR FOR SELECT id FROM tbl_2;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET _cur2Done = 1;
OPEN _cur_2;
LOOP2: LOOP
FETCH _cur_2 INTO variable2;
IF _cur2Done THEN
CLOSE _cur_2;
LEAVE LOOP2;
END IF;
END LOOP LOOP2;
END BLOCK2;
END LOOP LOOP1;
END BLOCK1;
END $$
DELIMITER ;