What are the possible reason of WordPress database error: [Query was empty]?

I have run into error below but it seems like I can't get proper error logs.

WordPress database error Query was empty for query made by

I had this codes that will throw almost similar to the error above.

$query_select = $wpdb->get_results($wpdb->prepare(
    " % "
    , 1
),ARRAY_A);

My question is, what are the possible codes that will throw query was empty like in my above code.

via Chebli Mohamed