连接多个表时Linq查询出错

Question

我的linq查询是：

 var query1 = (from grp in ctnx.tblGroupDatas
                     group grp by grp.MeterID_FK into g
                     let maxId = g.Max(gId => gId.GroupDataID)
                     select new { metId = g.Key, maxId });
 query2 = (from met in ctnx.tblMet
                      from mod in ctnx.tblMod.Where(mo => mo.ModID == met.Mod_FK).DefaultIfEmpty()
                      from grp in ctnx.tblGroupDatas.Where(gr => gr.Met_FK == met.MetID)
                      from group1 in db.tblMetRelateGroups.Where(x => x.Met_FK == met.MetID)

                      from q1 in query1.Where(q => q.metId == met.MetID && grp.GroupDataID == q.maxId)

                      where (group1.GroupMetID_FK == groupID)

                      select new
                      {
                          met.MetID,
                          mod.ModSerial,
                          met.MetSerial,
                          met.MetWaterSharingNo,
                          met.MetPowerSharingNo,
                          grp.GroupDate,
                          grp.GroupDataID
                      });
 var gridobisdata = query2.OrderByDescending(m => m.GroupDate);

但显示错误：

  

指定的LINQ表达式包含对查询的引用   与不同的背景相关联。