True story, I always forget where each value should be positioned for a left join on an update statement. This is always useful for a reference guide for me: UPDATE t1 LEFT JOIN t2 ON t2.id = t1.id SET t1.col1 = newvalue WHERE t2.id IS NULL Bookmark on Delicious Digg this post Recommend on Facebook share via Reddit Share with Stumblers Tweet about it Subscribe to the comments on this