Hi, I am using a Mysql table products which has a foreign key category_id on the categories table
the foreign key constraint is defined (Innodb engine). I noticed that when I run EXPLAIN SELECT * from products where category_id=1; it uses the foreign key, so I see type=Range and Key: my_foreign_key But when I run EXPLAIN SELECT * from products where category_id IN (1,10); it uses a full table scan: type=ALL, Key:NULL!!! Ironically, when I do EXPLAIN SELECT * from products where category_id IN (1,2); It uses type-range and Key: My_foreign_key! So I guess there is a problem when the category_id uses values that are not contiguous. Any ideas why? Thanks -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
