Make Update with select statement in Mysql

Question

I am trying to update for some products their category in Database. But I get an error and I don't understand where my statement is wrong. Please help. I want to find products that have in their name a specific word and after that I what to update the category for this products.

I want to select IDs from sho_posts where sho_posts.post_title contain this part of word '%Audio CD%' and after that to update the sho_term_relationships.term_taxonomy_id with value 2 where sho_term_relationships.object_id=sho_posts.id

UPDATE sho_term_relationships 
   SET term_taxonomy_id = 2
 WHERE object_id = (SELECT `id` FROM `1876522_shoping`.`sho_posts` WHERE CONVERT(`post_title` USING utf8) LIKE '%Audio CD%') 

Answer 1

In your WHERE clause, to find the ids to update based on the subquery results, use IN instead of =

UPDATE sho_term_relationships 
   SET term_taxonomy_id = 2
   WHERE object_id IN (
      SELECT `id` FROM `1876522_shoping`.`sho_posts` 
      WHERE CONVERT(`post_title` USING utf8) LIKE '%Audio CD%') 

You would use = only if you were certain the subquery would return a single row, it won't work if the subquery returns multiple rows. Using IN tests whether the object id is included in the subquery results.

Answer 2

You just need to use 'in' instead of '=' when updating multiple rows.

UPDATE sho_term_relationships SET term_taxonomy_id = 2 WHERE object_id in (SELECT id FROM 1876522_shoping . sho_posts WHERE CONVERT( post_title USING utf8) LIKE '%Audio CD%')