Fix tuple mapping issues

src/ServiceStack.OrmLite/Expressions/SqlExpression.Join.cs

@@ -229,7 +229,8 @@ public string SelectInto<TModel>()
 
             if (typeof(TModel) != typeof(List<object>) && 
                 typeof(TModel) != typeof(Dictionary<string, object>) &&
-                typeof(TModel) != typeof(object)) //dynamic
+                typeof(TModel) != typeof(object) && //dynamic
+                !typeof(TModel).IsValueTuple())
             {
                 selectDef = typeof(TModel).GetModelDefinition();
                 if (selectDef != modelDef && tableDefs.Contains(selectDef))

src/ServiceStack.OrmLite/OrmLiteUtils.cs

@@ -168,21 +168,19 @@ public static T ConvertToValueTuple<T>(this IDataReader reader, object[] values,
                 var field = typeFields.GetAccessor(itemName);
                 if (field == null) break;
 
-                var dbValue = values != null
-                    ? values[i]
-                    : reader.GetValue(i);
-
+                var fieldType = field.FieldInfo.FieldType;
+                var converter = dialectProvider.GetConverter(fieldType);
+                                
+                var dbValue = converter.GetValue(reader, i, values);
                 if (dbValue == null)
                     continue;
 
-                var fieldType = field.FieldInfo.FieldType;
                 if (dbValue.GetType() == fieldType)
                 {
                     field.PublicSetterRef(ref row, dbValue);
                 }
                 else
                 {
-                    var converter = dialectProvider.GetConverter(fieldType);
                     var fieldValue = converter.FromDbValue(fieldType, dbValue);
                     field.PublicSetterRef(ref row, fieldValue);
                 }

tests/ServiceStack.OrmLite.Tests/Issues/DynamicDataIssue.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using NUnit.Framework;
+using ServiceStack.DataAnnotations;
+using ServiceStack.Text;
+
+namespace ServiceStack.OrmLite.Tests.Issues
+{
+    public class ParentTbl
+    {
+        [AutoIncrement]
+        public long Id { get; set; }
+
+        public DateTime? DateMarried { get; set; }
+
+        [Reference]
+        public List<ChildTbl> Childs { get; set; } = new List<ChildTbl>();
+
+        public DateTime? DateOfBirth { get; set; }
+    }
+
+    public class ChildTbl
+    {
+        [AutoIncrement]
+        public long Id { get; set; }
+
+        [References(typeof(ParentTbl))]
+        public long ParentId { get; set; }
+
+        public DateTime? DateOfDeath { get; set; }
+    }
+
+
+    public class DynamicDataIssue : OrmLiteTestBase
+    {
+        private static void InitTables(IDbConnection db)
+        {
+            db.DropTable<ChildTbl>();
+            db.DropTable<ParentTbl>();
+            db.CreateTable<ParentTbl>();
+            db.CreateTable<ChildTbl>();
+        }
+
+        [Test] 
+        public void Can_select_null_DateTime_in_nullable_Tuple()
+        {
+            var date = new DateTime(2000,1,1);
+
+            using (var db = OpenDbConnection())
+            {
+                InitTables(db);
+
+                db.Insert(new ParentTbl { DateOfBirth = date });
+                db.Insert(new ParentTbl { DateOfBirth = null });
+
+                db.Select<ParentTbl>();
+                db.Select<(int, DateTime?)>(db.From<ParentTbl>());
+                db.Select<(int, DateTime?)>(db.From<ParentTbl>().Select(x => new { x.Id, x.DateOfBirth }));
+                db.Select<(int, DateTime)>(db.From<ParentTbl>().Select(x => new { x.Id, x.DateOfBirth }));
+            }
+        }
+
+        [Test]
+        public void Complex_example()
+        {
+            using (var db = OpenDbConnection())
+            {
+                InitTables(db);
+
+                var parentTbl = new ParentTbl { DateMarried = DateTime.Today };
+                parentTbl.Id = db.Insert(parentTbl, selectIdentity:true);
+                db.Insert(new ChildTbl { ParentId = parentTbl.Id, DateOfDeath = null });
+
+                var q = db.From<ChildTbl>()
+                    .RightJoin<ChildTbl, ParentTbl>((c, p) => c.ParentId == p.Id || c.Id == null)
+                    .GroupBy<ParentTbl>((p) => new { p.Id })
+                    .Select<ChildTbl, ParentTbl>((c, p) => new { p.Id, MaxKeyValuePeriodEnd = Sql.Max(c.DateOfDeath) });
+
+                var theSqlStatement = q.ToSelectStatement();
+
+                theSqlStatement.Print();
+            }
+        }
+
+    }
+}