The simplest of all possible SQL bundles....
* Edit the environment variables in the preferences to the values for your database
("Bundles" -> "Show Bundle Editor...", then select "MySQL prefs" under the "MySQL" bundle).
* Then open a file (your "worksheet"), type a SQL query, select it, and do "MySQL execute"
(or Ctrl-Cmd-Return).
* The query results are written back to the same worksheet. That's basically it.
SQL language file stolen from the SQL bundle.
Update 2011/1/14: Now with a new clever feature/cheesy hack! If you name your worksheet
file something like "worksheet.<database-name>.sql", then queries will automatically go
to that database -- so you can keep separate worksheets for different databases.