Mysql error #1064 when trying to create trigger - mysql

Question

I am trying to create a MySQL trigger but don't know why error #1064 occurs. Here is the full error message:
#1064 - 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 popularity_cur CURSOR FOR select (sum(tbl_reviews.vote_value)/count(tbl_' at line 22
Line #22 is close cur;
and here is what I've done so far:
delimiter //
CREATE TRIGGER business_popularity_trigger_after_review_insert
AFTER INSERT ON tbl_reviews FOR EACH ROW
BEGIN
DECLARE data_finished INTEGER DEFAULT 0;
DECLARE businessId, reviewId, dealId, businessServiceId INT DEFAULT 0;
DECLARE businessPopularity INTEGER DEFAULT 0;
DECLARE popularity_finished INTEGER DEFAULT 0;
DECLARE cur CURSOR FOR select tbl_reviews.review_id, tbl_reviews.deal_id, deals.deal_id, deals.business_service_id, business_services.business_service_id, business_services.business_id from tbl_reviews INNER JOIN deals ON deals.deal_id = new.deal_id INNER JOIN business_services ON business_services.business_service_id = deals.business_service_id
where tbl_reviews.review_id = new.review_id
group by business_services.business_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET data_finished = 1;
OPEN cur;
get_data: LOOP
fetch cur into reviewId, dealId, businessServiceId, businessId;
IF data_finished = 1 THEN
LEAVE get_data;
END IF;
END LOOP get_data;
close cur;
DECLARE popularity_cur CURSOR FOR select (sum(tbl_reviews.vote_value)/count(tbl_reviews.vote_value)) from tbl_reviews INNER JOIN business_services ON business_services.business_id = businessId INNER JOIN deals ON deals.business_service_id = business_services.business_service_id where deals.deal_is_deleted = 'N' and tbl_reviews.review_is_deleted = 'N' and tbl_reviews.review_status = 'Y';
set data_finished = 0;
IF businessId > 0 THEN
OPEN popularity_cur;
get_popularity: LOOP
fetch popularity_cur into businessPopularity;
IF data_finished = 1 THEN
LEAVE get_popularity;
END IF;
END LOOP get_popularity;
close popularity_cur;
Update business
set business.business_popularity = businessPopularity
where business.business_id = businessId;
END IF;
delimiter;
Please help me.
Thanks

Answer 1

You should use correct delimiter // at the end and close the BEGIN ... END construction. So change last lines to:
END IF;
END//
DELIMITER;
UPDATE Since you use aggregating functions SUM, COUNT you need GROUP BY statement. So try this way:
DECLARE popularity_cur CURSOR FOR
SELECT (sum(tbl_reviews.vote_value)/count(tbl_reviews.vote_value))
FROM tbl_reviews
INNER JOIN business_services
ON business_services.business_id = tbl_reviews.businessId
INNER JOIN deals
ON deals.business_service_id = business_services.business_service_id
AND deals.deal_is_deleted = 'N'
WHERE tbl_reviews.review_is_deleted = 'N'
AND tbl_reviews.review_status = 'Y'
GROUP BY tbl_reviews.businessId;
I did some optimization and you had wrong condition business_services.business_id = businessId so I did change to business_services.business_id = tbl_reviews.businessId.
NOTE Probably that wasn't a mistake and you need that business_services.business_id = businessId condition. But even if you need that you should use one condition for JOIN and another one to filter. so it could be like:
INNER JOIN business_services
ON business_services.business_id = tbl_reviews.business_id
AND business_services.business_id = businessId
UPDATE 2 According to the screenshot with your database schema your query could be like:
DECLARE popularity_cur CURSOR FOR
SELECT (sum(tbl_reviews.vote_value)/count(tbl_reviews.vote_value))
FROM tbl_reviews
INNER JOIN deals
ON tbl_reviews.deal_id = deals.deal_id
AND deals.deal_is_deleted = 'N'
INNER JOIN business_services
ON business_services.business_service_id = deals.business_service_id
WHERE tbl_reviews.review_is_deleted = 'N'
AND tbl_reviews.review_status = 'Y'
GROUP BY deals.business_service_id;