MySQL Forums
Forum List  »  Optimizer & Parser

Re: substr, update, index wont like each other
Posted by: Lars Johansson
Date: May 17, 2008 10:56PM

You should be able to see what goes on by an explain of your query.
I suspect the entire table2 is read for each row in table1, due to the substr.

This might not be a clean solution, but I would try creating a new column in table 2, which is the substr(a.column2_id,1,9) and then index and join on that column.

Options: ReplyQuote


Subject
Views
Written By
Posted
Re: substr, update, index wont like each other
2947
May 17, 2008 10:56PM


Sorry, you can't reply to this topic. It has been closed.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.