diff --git a/driver/error.cc b/driver/error.cc
index dce18ae47..5611561c8 100644
--- a/driver/error.cc
+++ b/driver/error.cc
@@ -488,7 +488,7 @@ MySQLGetDiagField(SQLSMALLINT handle_type, SQLHANDLE handle, SQLSMALLINT record,
     if (!stmt->result)
       *(SQLLEN *)num_value= 0;
     else
-      *(SQLLEN *)num_value= (SQLLEN) dbc->connection_proxy->num_rows(stmt->result);
+      *(SQLLEN *)num_value= (SQLLEN) stmt->dbc->connection_proxy->num_rows(stmt->result);
     return SQL_SUCCESS;
 
   case SQL_DIAG_DYNAMIC_FUNCTION: