mysql procedure syntax error - mysql

Question

I get an error by sending the following query (MYSQL 5.0):
DELIMITER //
CREATE PROCEDURE relationTable ()
BEGIN
DECLARE articlecount int;
DECLARE keywordcount int;
DECLARE articlehits int;
DECLARE ac int DEFAULT 0;
DECLARE kc int;
DECLARE articleid int;
DECLARE word varchar(100);
DECLARE word_id int;
SET articlehits = 0;
SET articlecount = (SELECT count(id) from articles);
SET keywordcount = (SELECT count(id) from keywords);
outerloop: WHILE (ac < articlecount) DO
SET kc = 0;
SET articleid = (SELECT id from articles LIMIT 1 OFFSET ac);
innerloop: WHILE (kc < keywordcount) DO
IF (articlehits < 5) THEN
SELECT keyword, id INTO word, word_id from keywords LIMIT 1 OFFSET kc;
IF (0 < (SELECT COUNT(id) from articles WHERE id=articleid AND CONCAT(title, " ",text) REGEXP word)) THEN
INSERT INTO articles (id, articleID, keywordID, type) VALUES(NULL, articleid, word_id, 'type1');
SET articlehits = articlehits + 1;
END IF;
SET kc = kc + 1;
ELSE
SET kc = keywordcount;
END IF;
END WHILE innerloop;
SET ac = ac + 1;
END WHILE outerloop;
END;
//
DELIMITER ;
This produces the following error:
ERROR 1064 (42000): 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 'LIMIT 1 OFFSET ac); innerloop: WHILE (kc <
keywordcount) DO TO word, word_id from' at line 15
Any idea why this happens?
(Wrote this to create a relation table between articles and keywords, to enable smart-links in article view.)

Answer 1

Try to remove the while labels:
WHILE (ac < articlecount) DO
SET kc = 0;
SET articleid = (SELECT id from articles LIMIT 1 OFFSET ac);
WHILE (kc < keywordcount) DO
IF (articlehits < 5) THEN
SELECT keyword, id INTO word, word_id from keywords LIMIT 1 OFFSET kc;
IF (0 < (SELECT COUNT(id) from articles WHERE id=articleid AND CONCAT(title, " ",text) REGEXP word)) THEN
INSERT INTO articles (id, articleID, keywordID, type) VALUES(NULL, articleid, word_id, 'type1');
SET articlehits = articlehits + 1;
END IF;
SET kc = kc + 1;
ELSE
SET kc = keywordcount;
END IF;
END WHILE;
SET ac = ac + 1;
END WHILE;

Answer 2

MySQL has connection-specific user-defined variables of the form #varname and declared procedure variables of the type you are using in your code sample. In my experience with procedures, sometimes only one of the types is allowed, and if I recall correctly, one of those situations may be when SELECTing INTO. You might try using user-defined variables here, as follows:
SET articleid = (SELECT id from articles LIMIT 1 OFFSET ac);
innerloop: WHILE (kc < keywordcount) DO
IF (articlehits < 5) THEN
SELECT keyword, id INTO #word, #word_id from keywords LIMIT 1 OFFSET kc;
Just an idea.

Answer 3

One problem may be the SET acticleid = (SELECT...). Try with SELECT .. INTO:
SELECT id INTO #articleid FROM articles LIMIT 1 OFFSET ac;
Variable LIMIT in stored procedures is only supported in new MySQL versions. Note that since you dont have an ORDER BY you will get a random row. It looks like you want to use a CURSOR instead. See docs.

Answer 4

At the risk of seeming over-critical, I believe you should rewrite this procedure to use cursors for traversing your databases, instead of individual selects with LIMIT.
see Cursors in MySQL Docs

Answer 5

Thank for your help so far.
The idea of Tom Haws proved to be correct. The variables for a SELECT INTO statement have to be user-defined.
I edited my code to use cursors, and user-defined variables as followed:
delimiter //
CREATE PROCEDURE relationTable ()
BEGIN
DECLARE articlehits int;
DECLARE looparticles int DEFAULT TRUE;
DECLARE loopwords int DEFAULT TRUE;
DECLARE done INT DEFAULT FALSE;
DECLARE keywordcursor CURSOR FOR SELECT keyword, id FROM keywords;
DECLARE articlecursor CURSOR FOR SELECT id FROM articles;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN articlecursor;
WHILE (looparticles) DO
FETCH articlecursor INTO #articleid;
IF done THEN SET looparticles = FALSE;
ELSE
SET articlehits = 0;
OPEN keywordcursor;
WHILE (loopwords) DO
FETCH keywordcursor INTO #word, #wordid;
IF (articlehits < 5) AND NOT done THEN
IF (0 < (SELECT COUNT(id) FROM articles WHERE id=#articleid AND CONCAT(title, " ", text) REGEXP #word)) THEN
INSERT INTO keyword_article_rel (id, meldungID, wordID) VALUES(NULL, #articleid, #wordid);
SET articlehits = articlehits + 1;
END IF;
ELSE
SET loopwords = FALSE;
CLOSE keywordcursor;
SET done = FALSE;
END IF;
END WHILE;
END IF;
END WHILE;
CLOSE articlecursor;
END;
//
delimiter ;
And now I get an other error that I really can't explain:
ERROR 1064 (42000): 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 '; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN articlecursor; W' at line 6
This error confuses me because it can't have a problem with the handler. The handler is declared as in the example of the mysql-documentation. Could the problem be that I can't create two cursors like this?