diff --git a/server/imserver/dbhelper.cc b/server/imserver/dbhelper.cc
index 9883d68..9e30918 100644
--- a/server/imserver/dbhelper.cc
+++ b/server/imserver/dbhelper.cc
@@ -199,7 +199,7 @@ void DBHelper::ShuaOfflineUsers(Player* hum)
 {
     std::set<std::string>& exclude_account_ids = hum->GetExcludeAccountIds();
     if (cache_users_hash.size() < 500 && !exclude_account_ids.empty()) {
-        std::string fmtstr;
+        std::string fmtstr = "'',";
         std::vector<a8::XValue> sql_params;
         for (auto& account_id : exclude_account_ids) {
             fmtstr += "'%s',";
@@ -242,7 +242,7 @@ void DBHelper::ShuaOfflineUsers(Player* hum)
               "SELECT idx, account_id, nickname, avatar_url, sex, data_version1, user_value1, "
               "   user_value2, user_value3, last_logintime "
               "FROM `user` WHERE idx > (SELECT 9999 + FLOOR(RAND() * (MAX(idx) - 10000)) FROM `user`)"
-              "   AND account_id not in(" + fmtstr + ") LIMIT 1, 10;"
+              "   AND account_id NOT IN(" + fmtstr + ") LIMIT 1, 10;"
               ).c_str(),
              sql_params,
              a8::XParams()