MySQL Set Variables in While-Loop with If-Condition - mysql

Question

I am working on a procedure which is doing the following:
With a cursor declared I want to go through all entries of a table to find entries where the given period is covering the one from the cursor.
Example: a student A went to school at grade x from date 3 to date 6. Let's find all who studied with him at least one time for the same class.
The while-loop would be applied to the same table. But I want to just find out if there is at least one entry or not. So the while loop should stop if the first entry appears.
Example: A student B could have visited the same class as A did. But for a year he has been in another class. Just for example.
And here is my problem. I have two variables to set and I get a syntax error.
DELIMITER $$
DROP PROCEDURE IF EXISTS coworkers$$
CREATE PROCEDURE coworkers(
IN gus INT,
IN rus INT,
OUT gto INT
)
BEGIN
DECLARE recCID INT;
DECLARE recSDT DATE;
DECLARE recEDT DATE;
DECLARE done INT DEFAULT FALSE;
DECLARE ctr INT;
DECLARE cwrk CURSOR FOR
SELECT comp_id, start_date, end_date FROM skill_cv_test WHERE usr_id = rus;
DECLARE CONTINUE HANDLER
FOR NOT FOUND
SET done = TRUE;
OPEN cwrk;
SET ctr = 0;
loop_cwrk: WHILE(ctr<1) DO
FETCH cwrk INTO recCID, recSDT, recEDT;
IF EXISTS
(SELECT *
FROM skill_cv_test AS m
WHERE m.usr_Id = gus AND m.usr_id != rus AND (m.start_date < recSDT OR m.end_date <= recEDT) AND m.comp_id = recCID)
THEN
SET ctr = 1,
SET gto = 1;
IF done THEN
LEAVE loop_cwrk;
END IF;
END WHILE loop_cwrk;
CLOSE cwrk;
end $$
delimiter ;
CALL coworkers(2,1,#gto);
I have tried different formats for the section THEN SET... which is the problem.
Here is the error code:
You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near ''ctr' := 1,
SET 'gto' ;= 1;
Here you can see what else I have tried (among others). Probably it's a totally wrong approach.
Btw: the Select within the loop is only a placeholder to get the whole procedure work.
But now, what am I doing wrong?
Thanks in advance.
SOLUTION
DELIMITER $$
DROP PROCEDURE IF EXISTS coworkers$$
CREATE PROCEDURE coworkers(
IN gus INT,
IN rus INT,
OUT gto INT
)
BEGIN
DECLARE recCID INT;
DECLARE recSDT DATE;
DECLARE recEDT DATE;
DECLARE done INT DEFAULT FALSE;
DECLARE ctr INT;
DECLARE cwrk CURSOR FOR
SELECT comp_id, start_date, end_date FROM skill_cv_test WHERE usr_id = rus;
DECLARE CONTINUE HANDLER
FOR NOT FOUND
SET done = TRUE;
OPEN cwrk;
SET ctr = 0;
loop_cwrk: WHILE(ctr<1) DO
FETCH cwrk INTO recCID, recSDT, recEDT;
IF EXISTS
(SELECT *
FROM skill_cv_test AS m
WHERE m.usr_Id = gus AND m.usr_id != rus AND (m.start_date < recSDT
OR m.end_date <= recEDT) AND m.comp_id = recCID)
THEN
SET ctr = 1;
SET gto = 1;
END IF;
IF done THEN
LEAVE loop_cwrk;
END IF;
END WHILE loop_cwrk;
CLOSE cwrk;
end $$
delimiter ;
CALL coworkers(2,1,#gto);

Answer 1

You need add END IF for your first IF
IF EXISTS
(SELECT *
FROM skill_cv_test AS m
WHERE m.usr_Id = gus AND m.usr_id != rus AND (m.start_date < recSDT
OR m.end_date <= recEDT) AND m.comp_id = recCID)
THEN
SET ctr = 1;
SET gto = 1;
END IF; -- Add END IF here
IF done THEN
LEAVE loop_cwrk;
END IF;