diff --git a/FreeSql.Tests/FreeSql.Tests/Sqlite/Curd/SqliteUpdateTest.cs b/FreeSql.Tests/FreeSql.Tests/Sqlite/Curd/SqliteUpdateTest.cs
index e6a4bbf8..c0066315 100644
--- a/FreeSql.Tests/FreeSql.Tests/Sqlite/Curd/SqliteUpdateTest.cs
+++ b/FreeSql.Tests/FreeSql.Tests/Sqlite/Curd/SqliteUpdateTest.cs
@@ -156,6 +156,9 @@ namespace FreeSql.Tests.Sqlite
             sql = update.Set(a => a.Clicks * incrv / 1).Where(a => a.Id == 1).ToSql().Replace("\r\n", "");
             Assert.Equal("UPDATE \"tb_topic\" SET \"Clicks\" = ifnull(\"Clicks\", 0) * 10 / 1 WHERE (\"Id\" = 1)", sql);
 
+            sql = update.Set(a => a.Title + "xxxx").Where(a => a.Id == 1).ToSql().Replace("\r\n", "");
+            Assert.Equal("UPDATE \"tb_topic\" SET \"Title\" = ifnull(\"Title\", '') || 'xxxx' WHERE (\"Id\" = 1)", sql);
+
             sql = update.Set(a => a.Id - incrv).Where(a => a.Id == 1).ToSql().Replace("\r\n", "");
             Assert.Equal("UPDATE \"tb_topic\" SET \"Id\" = (\"Id\" - 10) WHERE (\"Id\" = 1)", sql);
 
diff --git a/FreeSql/Internal/CommonProvider/UpdateProvider.cs b/FreeSql/Internal/CommonProvider/UpdateProvider.cs
index 5e6a3bef..d928fa87 100644
--- a/FreeSql/Internal/CommonProvider/UpdateProvider.cs
+++ b/FreeSql/Internal/CommonProvider/UpdateProvider.cs
@@ -622,6 +622,11 @@ namespace FreeSql.Internal.CommonProvider
                     if (replval == null) continue;
                     var replname = _commonUtils.QuoteSqlName(col.Column.Attribute.Name);
                     expt = expt.Replace(replname, _commonUtils.IsNull(replname, _commonUtils.FormatSql("{0}", replval)));
+                } 
+                else if (col.Column.CsType == typeof(string))
+                {
+                    var replname = _commonUtils.QuoteSqlName(col.Column.Attribute.Name);
+                    expt = expt.Replace(replname, _commonUtils.IsNull(replname, _commonUtils.FormatSql("{0}", "")));
                 }
             }
             _setIncr.Append(", ").Append(_commonUtils.QuoteSqlName(cols.First().Column.Attribute.Name)).Append(" = ").Append(expt);