$cat_id = $this->category;
$query = $DB->get_record_sql('select name from mdl_question_categories where id="' . $cat_id . '"');
print($query->name);
$cat_id = $this->category;
$query = $DB->get_record_sql('select name from mdl_question_categories where id="' . $cat_id . '"');
print($query->name);
Thanks for posting Charlie, that should work but you should consider something like
$DB->get_record('question_categories',['id'=>$cat_id)
Then it will work if someone has a prefix other than mdl.
See
https://docs.moodle.org/dev/Data_manipulation_API#Main_info
I suspect most people most of the time leave the default mdl_ but it is nice to cover unusual situations.
Thanks Marcus,
It's good to see an elegant approach.