diff --git a/neutrino-proxy-server/src/main/resources/mapper/PortGroupMapper.xml b/neutrino-proxy-server/src/main/resources/mapper/PortGroupMapper.xml
index a88f0263..81d58e84 100644
--- a/neutrino-proxy-server/src/main/resources/mapper/PortGroupMapper.xml
+++ b/neutrino-proxy-server/src/main/resources/mapper/PortGroupMapper.xml
@@ -9,7 +9,7 @@
                    u.`name`
                WHEN g.possessor_type = 2 THEN
                    l.`name`
-               ELSE ""
+               ELSE ''
                END possessor
     FROM port_group g
              LEFT JOIN `user` u ON g.possessor_id = u.id