diff --git a/src/Archiver/Commands/ExportTableCommand.cs b/src/Archiver/Commands/ExportTableCommand.cs
index 1f837bc..bbd602f 100644
--- a/src/Archiver/Commands/ExportTableCommand.cs
+++ b/src/Archiver/Commands/ExportTableCommand.cs
@@ -182,7 +182,7 @@ namespace Chenfeng.MES.Archiver.Commands
                             switch (val)
                             {
                                 case System.DBNull b:
-                                    row.Add("null");
+                                    newVal = "null";
                                     break;
                                 case bool b:
                                     newVal = b ? 1 : 0;
@@ -207,6 +207,7 @@ namespace Chenfeng.MES.Archiver.Commands
                             }
                         }
                         valString.Append(')');
+                        valString.Append(',');
                         //valString.Append($"({string.Join(",", row)}),");
                     }
                     if (valString.Length == 0) break;