Procedure in MySQL with LOOP - mysql

Question

I'm really struggling with this LOOP in my procedure. I can't understand what the error means. I guess anyone can just try to run this without any knowledge of the database...
DROP PROCEDURE IF EXISTS removeDuplicates;
DELIMITER $$
CREATE PROCEDURE removeDuplicates(str TEXT)
BEGIN
DECLARE temp_word TEXT;
DECLARE last_word TEXT;
DECLARE result TEXT;
DECLARE finished INT DEFAULT false;
DECLARE words_cursor CURSOR FOR
SELECT word FROM explosion;
DECLARE CONTINUE handler FOR NOT found
SET finished = true;
CALL explode(str);
DROP TABLE IF EXISTS temp_words;
CREATE TABLE temp_words (id INT AUTO_INCREMENT PRIMARY KEY NOT NULL, t VARCHAR(100));
OPEN words_cursor;
loop_words: LOOP
FETCH words_cursor INTO temp_word;
IF finished THEN
LEAVE loop_words;
IF temp_word = "" THEN
SET result = CONCAT(result, temp_word, " ");
SET last_word = temp_word;
ELSEIF last_word = temp_word THEN
SET last_word = temp_word;
ELSE
INSERT INTO temp_words (t) VALUES (temp_word);
END IF;
END LOOP loop_words;
CLOSE words_cursor;
RETURN result;
END$$
DELIMITER ;
Any pointers would be gratefully received. The error I am getting is:
[ERROR in query 2] 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 'LOOP loop_words;
CLOSE words_cursor;
RETURN result;
END' at line 29
I'm sure it must be something simple, but I'll be damned if I can work it out.
Thanks, Chris

Answer 1

DROP PROCEDURE IF EXISTS removeDuplicates;
DELIMITER $$
CREATE PROCEDURE removeDuplicates(str TEXT , OUT OUT_STR_RESULT TEXT)
BEGIN
DECLARE temp_word TEXT;
DECLARE last_word TEXT;
DECLARE result TEXT;
DECLARE finished INT DEFAULT false;
DECLARE words_cursor CURSOR FOR
SELECT word FROM explosion;
DECLARE CONTINUE handler FOR NOT found
SET finished = true;
CALL explode(str);
DROP TABLE IF EXISTS temp_words;
CREATE TABLE temp_words (id INT AUTO_INCREMENT PRIMARY KEY NOT NULL, t VARCHAR(100));
OPEN words_cursor;
loop_words: LOOP
FETCH words_cursor INTO temp_word;
IF finished THEN
LEAVE loop_words;
IF temp_word = "" THEN
SET result = CONCAT(result, temp_word, " ");
SET last_word = temp_word;
ELSEIF last_word = temp_word THEN
SET last_word = temp_word;
ELSE
INSERT INTO temp_words (t) VALUES (temp_word);
END IF;
END IF; -- i had made changes at this line.
END LOOP loop_words;
CLOSE words_cursor;
SET OUT_STR_RESULT =result;
-- RETURN result;
END$$
;
You missed one END IF.
One more thing: you can't put RETURN statement in procedure; it's only allowed in FUNCTION. Instead of that you can use OUT parameter for same.
Try above code.