WithSql存在GroupBy时，自定义返回列，主键key无法正常as为自定义的指定列名

[sunnyfancore]

问题描述及重现步骤：

ISelect<WorkReportCountObj> iSelect = _freeSql.Select<WorkReportCountObj>()
                  .WithSql( //待审批
                     _freeSql.Select<SysCheckForm, SysMessage>()
                     .InnerJoin((a1, a2) => a1.Id == a2.WorkId)
                     .Where((a1, a2) => a2.Type == 1 && a2.IsDelete == 1 && postIds.Contains(a2.UserDepartmentPostId))
                     .WhereIf(searchDto.start_time.HasValue, (a1, a2) => a2.RecvDate >= searchDto.start_time)
                     .WhereIf(searchDto.end_time.HasValue, (a1, a2) => a2.RecvDate <= searchDto.end_time)
                     .GroupBy((a1, a2) => a2.UserDepartmentPostId)
                     .ToSql(r1 => new WorkReportCountObj()
                     {
                         uid = r1.Key,
                         count = r1.Count(),
                         type = 1,
                         id_type = 2
                     }, FieldAliasOptions.AsProperty))；

上述语句会输出SELECT UserDepartmentPostId 而不是我想要的SELECT UserDepartmentPostId AS uid

当语句为以下时，可以正常输出

 ISelect<WorkReportCountObj> iSelect = _freeSql.Select<WorkReportCountObj>()
                  .WithSql( //待审批
                     _freeSql.Select<SysCheckForm, SysMessage>()
                     .InnerJoin((a1, a2) => a1.Id == a2.WorkId)
                     .Where((a1, a2) => a2.Type == 1 && a2.IsDelete == 1 && postIds.Contains(a2.UserDepartmentPostId))
                     .WhereIf(searchDto.start_time.HasValue, (a1, a2) => a2.RecvDate >= searchDto.start_time)
                     .WhereIf(searchDto.end_time.HasValue, (a1, a2) => a2.RecvDate <= searchDto.end_time)
                     .GroupBy((a1, a2) => a2.UserDepartmentPostId)
                     .ToSql(r1 => new WorkReportCountObj()
                     {
                         uid = r1.Value.Item2.UserDepartmentPostId,
                         count = r1.Count(),
                         type = 1,
                         id_type = 2
                     }, FieldAliasOptions.AsProperty))

输出语句为SELECT UserDepartmentPostId AS uid ，此输出是正确的

数据库的具体版本

mysql5.7

安装的包

.net framework/. net core？ 及具体版本

. net core3.1