[irn-bru]

Open admin/index.php

Find This Line:

makenavselect("Options","<hr>");

Above This Line put:

makenavoption("Run a SQL query", "query.php?s=$session[sessionhash]","<br>");

There will be a Run a SQL query link under Options
use that to run your SQL query.

Just to note I havent used this addon, but in the thread Firefly recommends you use another hack I dont know why.

I would have to read the full thread which I havent. I suggest you do that, and use the other hack as there must be reasson for it been closed.