SELECT  [t6].[CourseID] ,
        [t6].[UserID] ,
        [t6].[CourseName] ,
        [t6].[ResourceID] ,
        [t6].[StudyTime] ,
        [t6].[BeginTime] ,
        [t6].[EndTime] ,
        [t6].[value] AS [CategoryID] ,
        [t6].[value2] AS [ClassHour] ,
        [t6].[value3] AS [Percent] ,
        [t6].[test] ,
        [t6].[ID] ,
        [t6].[SmallPicture]
FROM    dbo.User_Course AS t6
        LEFT  OUTER JOIN [User_StudyRecord] AS t3 ON t6.UserID = t3.UserID
                                                     AND t3.ResourceID = t6.ResourceID

            var linq = from _data in new User_Course(UnitOfWork).GetEntities()
                       let list = new Res_Item(UnitOfWork).GetEntities().Select(t => new Entity.Res_Item
                       {
                           ID = t.ID,
                           SmallPicture = t.SmallPicture,
                       }).Where(i => i.ID == _data.ResourceID)
           
                       let list2 = new User_StudyRecord(UnitOfWork).GetModel().Select(r => new Entity.User_StudyRecord
                       {
                           StudyContent = r.StudyContent,
                           UserID = r.UserID,
                           Res_ItemID = r.Res_ItemID,
                       }).Where(i => i.Res_ItemID == _data.ResourceID && i.UserID == _data.UserID)
                       from record in list2.DefaultIfEmpty()
                       where _data.CategoryID != (int)CustomEnum.CategoryType.BroadcastProgram
                       && _data.CategoryID != (int)CustomEnum.CategoryType.AskRoom
                       select new Entity.User_Course
                       {
                           CourseID = _data.CourseID,
                           UserID = _data.UserID,
                           CourseName = _data.CourseName,
                           ResourceID = _data.ResourceID,
                           StudyTime = _data.StudyTime,
                           BeginTime = _data.BeginTime,
                           EndTime = _data.EndTime,
                           CategoryID = _data.CategoryID ?? 2,
                           Res_Item = list.FirstOrDefault(),
                           ClassHour = _data.ClassHour ?? 0,
                           Percent = _data.Percent ?? 0,
                           Prev_ResourceName = record == null ? string.Empty : record.StudyContent,
                       };