The corresponding phpMyAdmin feature, along with Josh's Stylesheet Popularity hack, gave me this idea.
What about a hack that lets you "bookmark" commonly used MySQL queries, so that you can execute them by selection from a menu?
This could save having to write a lot of individual hacks.
Each bookmarked query would consist of a name and the query text. Maybe a description field would be helpful too. The bookmarks would be stored in a new database table.
It might be simplest to add this to the Admin -> SQL command page.