diff --git a/Src/Asp.NetCore2/SqlSugar/Abstract/FastestProvider/Private.cs b/Src/Asp.NetCore2/SqlSugar/Abstract/FastestProvider/Private.cs
index bda83a193..0b6dc0dca 100644
--- a/Src/Asp.NetCore2/SqlSugar/Abstract/FastestProvider/Private.cs
+++ b/Src/Asp.NetCore2/SqlSugar/Abstract/FastestProvider/Private.cs
@@ -125,11 +125,11 @@ namespace SqlSugar
                 var tempColumns = tempDataTable.Columns.Cast<DataColumn>().Select(it=>it.ColumnName);
                 columns = columns.Where(it => tempColumns.Any(s => s.EqualCase(it.DbColumnName))).ToList();
             }
-            var (isDiscrimator, discrimatorDict) = GetDiscrimator();
+            MyTuple myTuple = GetDiscrimator();
 
-            if (isDiscrimator && discrimatorDict?.Count > 0)
+            if (myTuple.isDiscrimator && myTuple.discrimatorDict?.Count > 0)
             {
-                foreach (var dict in discrimatorDict)
+                foreach (var dict in myTuple.discrimatorDict)
                 {
                     if (!dt.Columns.Contains(dict.Key))
                         dt.Columns.Add(dict.Key);
@@ -199,9 +199,9 @@ namespace SqlSugar
                     }
                     dr[name] = value;
                 }
-                if (isDiscrimator && discrimatorDict?.Count > 0)
+                if (myTuple.isDiscrimator && myTuple.discrimatorDict?.Count > 0)
                 {
-                    foreach (var dict in discrimatorDict)
+                    foreach (var dict in myTuple.discrimatorDict)
                     {
                         var key = dict.Key; var val = dict.Value;
                         if (!string.IsNullOrWhiteSpace(val) && string.IsNullOrWhiteSpace(dr[key] + ""))
@@ -393,7 +393,7 @@ namespace SqlSugar
             }
         }
 
-        private (bool isDiscrimator, Dictionary<string, string> discrimatorDict) GetDiscrimator()
+        private MyTuple GetDiscrimator()
         {
             var isDiscrimator = entityInfo.Discrimator.HasValue();
             var dict = new Dictionary<string, string>();
@@ -405,12 +405,24 @@ namespace SqlSugar
                 {
                     var name = disItem.Split(':').First();
                     var value = disItem.Split(':').Last();
-                    dict.TryAdd(name, value);
+                    if(!dict.ContainsKey(name))
+                       dict.Add(name, value);
                 }
-            }
-
-            return (isDiscrimator, dict);
+            } 
+            return new MyTuple(isDiscrimator, dict);
         }
 
     }
+
+    internal class MyTuple
+    {
+        public bool isDiscrimator;
+        public Dictionary<string, string> discrimatorDict;
+
+        public MyTuple(bool isDiscrimator, Dictionary<string, string> dict)
+        {
+            this.isDiscrimator = isDiscrimator;
+            this.discrimatorDict = dict;
+        }
+    }
 }
diff --git a/Src/Asp.NetCore2/SqlSugar/ExpressionsToSql/Subquery/SubResolve.cs b/Src/Asp.NetCore2/SqlSugar/ExpressionsToSql/Subquery/SubResolve.cs
index c56a76726..cfb72be0f 100644
--- a/Src/Asp.NetCore2/SqlSugar/ExpressionsToSql/Subquery/SubResolve.cs
+++ b/Src/Asp.NetCore2/SqlSugar/ExpressionsToSql/Subquery/SubResolve.cs
@@ -312,14 +312,14 @@ namespace SqlSugar
                 {
                     hasNolock = true;
                 }
-                var result = it.GetValue(it.Expression);
-                var isJoin = (it is SubLeftJoin || it is SubInnerJoin);
+                var innerResult = it.GetValue(it.Expression);
+                var innerIsJoin = (it is SubLeftJoin || it is SubInnerJoin);
                 var isSqlServer =UtilMethods.GetDatabaseType(this.context) == DbType.SqlServer;
-                if (hasNolock && isJoin&& isSqlServer)
+                if (hasNolock && innerIsJoin&& isSqlServer)
                 {
-                    result = result.Replace("] ON (", "] " + SqlWith.NoLock + " ON (");
+                    innerResult = innerResult.Replace("] ON (", "] " + SqlWith.NoLock + " ON (");
                 }
-                return result;
+                return innerResult;
             }).ToList();
             if (this.context?.SugarContext?.Context?.CurrentConnectionConfig?.DbType == DbType.Oracle && isubList.Any(s => s is SubSelect) && isubList.Any(s => s is SubOrderBy || s is SubOrderByDesc))
             {