Searching serialized data, using active record
It's just a trick to not slow your application. You have to use .to_yaml.
exact result:
MyModel.where("mycode = ?", [43565, 43402].to_yaml)
#=> [#<MyModel id:...]
Tested only for MySQL.
Basically, you can't. The downside of #serialize is that you're bypassing your database's native abstractions. You're pretty much limited to loading and saving the data.
That said, one very good way to slow your application to a crawl could be:
MyModel.all.select { |m| m.mycode.include? 43402 }
Moral of the story: don't use #serialize for any data you need to query on.