How to search across all databases

I guess this is more of a mysql question then about the plugin, but how could I search for a table across all the databases?

I have a stats plugin that can be activated on a user-by-user basis, but now that I have 256 databases I dont know how can I search for all the users that have activated the plugin.

I used show tables like 'wp_%_statpress'; before, but now I dont know what to do.