MySQL update a joined table

Question

I want to update a table in a statement that has several joins. While I know the order of joins doesn\'t really matter (unless you you are using optimizer hints) I ordered

Answer 1

You have the ordering of the statements wrong. You can read up on the syntax here (I know, it's pretty hard to read.

UPDATE tableA a
  JOIN tableB b
    ON a.a_id = b.a_id
  JOIN tableC c
    ON b.b_id = c.b_id
   SET b.val = a.val+c.val
 WHERE a.val > 10
   AND c.val > 10;

sql fiddle