Question

I’ve got this query that should refund people half the stuff they bought in the past week:

UPDATE main_data SET md.amount_current = md.amount_current + (bought.total / 2) 
FROM main_data AS md 
INNER JOIN (
    SELECT DISTINCT sb.user_id, SUM(sb.spend) AS total 
    FROM shopitems_bought AS sb 
    LEFT JOIN shopitems AS si 
    ON sb.shopitem_id = si.id 
    WHERE sb.date_bought <= '2012-03-09' 
    AND sb.date_bought > DATE_ADD('2012-03-09', INTERVAL -7 DAY) 
    AND si.valid = 1 
    GROUP BY sb.user_id
) AS bought ON bought.user_id = md.user_id 
WHERE md.valid = 1

The SELECT part executes just fine on its own and returns the right data (IDs that should be refunded and how much they spend in that week). However the query as a whole throws an error saying I have an error in my SQL syntax near line 2 (I quote: ‘FROM main_data AS md INNER JOIN ( SELECT DISTINCT sb.forum_id, SUM(sb.s’).

I can’t see what I’m doing wrong.

Answer 1

MySql uses a different syntax for join with update statements than what you’re using above. Try changing your query to:

UPDATE main_data md 
INNER JOIN (
    SELECT DISTINCT sb.user_id, SUM(sb.spend) AS total 
    FROM shopitems_bought AS sb 
    LEFT JOIN shopitems AS si 
    ON sb.shopitem_id = si.id 
    WHERE sb.date_bought <= '2012-03-09' 
    AND sb.date_bought > DATE_ADD('2012-03-09', INTERVAL -7 DAY) 
    AND si.valid = 1 
    GROUP BY sb.user_id
) bought ON bought.user_id = md.user_id 
SET amount_current = md.amount_current - (bought.total / 2) 
WHERE md.valid = 1

Note, I changed

SET amount_current = md.amount_current + (bought.total / 2) 

To subtract instead of add:

SET amount_current = md.amount_current - (bought.total / 2)