The Multi-Table Query Generator - Mastering phpMyAdmin 3.1 for Effective MySQL Management - page 209

Another click on the Update Query button produces the following screen:
Now, you can see that there are two additional criteria rows (which are empty at the
moment). We can also remove criteria rows. This can be done by choosing negative
numbers in the Add/Delete Criteria Row dialog, or by ticking the Del checkbox
beside the row(s) we want to remove. Let's remove the two rows we've just added.
as we don't need them now. The Update Query button refreshes the page with the
specified adjustment.