From 7533f810205e43cba5b87af7efe24c99ee1177d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E9=BB=91=E5=85=94?= <173592829@qq.com>
Date: Thu, 11 Jun 2020 21:58:02 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BF=AE=E5=A4=8D=20MYSQL=20BulkInsert=20Null?=
 =?UTF-8?q?=E5=80=BC=E9=97=AE=E9=A2=98=E3=80=82?=
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---
 src/SmartSql.Bulk.MySql/BulkInsert.cs | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/SmartSql.Bulk.MySql/BulkInsert.cs b/src/SmartSql.Bulk.MySql/BulkInsert.cs
index f5c7d6eb..1e1a817d 100644
--- a/src/SmartSql.Bulk.MySql/BulkInsert.cs
+++ b/src/SmartSql.Bulk.MySql/BulkInsert.cs
@@ -16,6 +16,7 @@ namespace SmartSql.Bulk.MySql
 {
     public class BulkInsert : AbstractBulkInsert
     {
+        const string NULL_VALUE = "NULL";
         public BulkInsert(IDbSession dbSession) : base(dbSession)
         {
         }
@@ -85,18 +86,22 @@ private string ToCSV()
                         var originCell = row[dataColumn];
                         if (originCell is DBNull)
                         {
-                            dataBuilder.Append(DBNull.Value);
+                            dataBuilder.Append(NULL_VALUE);
                         }
                         else
                         {
-                            var dateCell = (DateTime) originCell;
+                            var dateCell = (DateTime)originCell;
                             var dateCellTime = dateCell.ToString(DateTimeFormat);
                             dataBuilder.Append(dateCellTime);
                         }
                     }
+                    else if (row[dataColumn] is DBNull || dataColumn.AutoIncrement)
+                    {
+                        dataBuilder.Append(NULL_VALUE);
+                    }
                     else
                     {
-                        var colValStr = dataColumn.AutoIncrement ? "" : row[dataColumn]?.ToString();
+                        var colValStr = row[dataColumn]?.ToString() ?? NULL_VALUE;
                         dataBuilder.Append(colValStr);
                     }