MySQL update join with limit

Question

I would like to know how to update a table, with values from another table, by the trick is I need to set a limit because I have thousands of rows to update, and PHPmyadmin can\

Answer 1

You can try it this way

UPDATE wp_postmeta t JOIN
(
    SELECT p.meta_id, m.newmap
      FROM wp_postmeta p JOIN wp_map m
        ON p.meta_value = m.oldmap
     ORDER BY p.meta_id
     LIMIT 100
) s
   ON t.meta_id = s.meta_id
  SET t.meta_value = s.newmap;

Here is SQLFiddle demo