diff --git a/Src/Asp.NetCore2/SqlSeverTest/UserTestCases/UnitTest/Unitdafadsyssww.cs b/Src/Asp.NetCore2/SqlSeverTest/UserTestCases/UnitTest/Unitdafadsyssww.cs
new file mode 100644
index 000000000..20330a0d9
--- /dev/null
+++ b/Src/Asp.NetCore2/SqlSeverTest/UserTestCases/UnitTest/Unitdafadsyssww.cs
@@ -0,0 +1,54 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using SqlSugar;
+namespace OrmTest
+{
+    public  class Unitdfassyss
+    {
+        public static void Init()
+        {
+            var db = NewUnitTest.Db;
+            //建表 
+            db.CodeFirst.InitTables<NoKeyTable, MayHaveKeyTable>();
+            //清空表
+            db.DbMaintenance.TruncateTable<NoKeyTable>();
+            var enableKey = false;
+            var result = db.Queryable<NoKeyTable>()
+                .Cast<MayHaveKeyTable>()
+                .Select(t => new
+                {
+                    t.id,
+    
+                    key = enableKey ? t.key : null
+                })
+                .ToList();
+            enableKey = true;
+            var result2 = db.Queryable<MayHaveKeyTable>()
+             .Cast<MayHaveKeyTable>()
+             .Select(t => new
+             {
+                 t.id,
+
+                 key = enableKey ? t.key : null
+             })
+             .ToList();
+
+            Console.WriteLine(result);
+            Console.WriteLine("用例跑完");
+            Console.ReadKey();
+        }
+        //建类
+        public class NoKeyTable
+        {
+            public int id { get; set; }
+        }
+
+        public class MayHaveKeyTable
+        {
+            public int id { get; set; }
+            public string? key { get; set; }
+        }
+    }
+}
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