affected rows are returned in case of DELETE with no WHERE clause, at least since MySQL 4.0.x

sql.php

@@ -353,7 +353,9 @@ else {
     // If the query is a DELETE query with no WHERE clause, get the number of
     // rows that will be deleted (mysql_affected_rows will always return 0 in
     // this case)
+    // Note: testing shows that this no longer applies since MySQL 4.0.x 
 
+    if (PMA_MYSQL_INT_VERSION < 40000) {
         if ($is_delete
             && preg_match('@^DELETE([[:space:]].+)?(FROM[[:space:]](.+))$@i', $sql_query, $parts)
             && !preg_match('@[[:space:]]WHERE[[:space:]]@i', $parts[3])) {
@@ -365,6 +367,7 @@ else {
                 $num_rows   = 0;
             }
         }
+    }
 
     //  E x e c u t e    t h e    q u e r y