CourseDateAndRoomBookingExporter: fixed error with ex_dates and course_name

classes/exporters/CourseDateAndRoomBookingExporter.class.php

@@ -592,7 +592,7 @@ class CourseDateAndRoomBookingExporter extends Exporter
             }
             $course_dates_stmt_sql .= implode(', ', $fields_sql) . ' ';
             $course_dates_stmt_sql .= "FROM ex_termine ";
-            if ($institute_ids) {
+            if ($institute_ids || $with_course_name) {
                 $course_dates_stmt_sql .= "INNER JOIN `seminare`
                     ON `ex_termine`.`range_id` = `seminare`.`seminar_id` ";
             }