I stumbled across two lightweight web-based database administration tools: php Mini Admin and QDBA. Both are single PHP files, so you can just upload them to a server, specify your database login information, and be able to browse tables, edit data, and do other administrative tasks without installing the effective-but-heavy phpMyAdmin or allowing direct remote database access to your MySQL server.

Note that you should still take proper security measures when using these web-based tools (SSL, restrict access using ACLs or IP, don't let users log in as root), but overall they're easy & helpful. Of the two, QDBA is more attractive & usable, but is primarily used to view and edit data. phpMiniAdmin is spartan but offers many additional built-in features like import/export, table optimization & repair, and other "DBA" tasks. Both tools offer a SQL query window were you can execute raw SQL commands against the server.

phpMiniAdmin Screenshot:

QDBA Screenshot