ef not in和 GroupBy 分组

//ef 分组 排序 之后取第一行 
List<InstrStateDetail> listGroupPost = this.Select().GroupBy(i => i.InstrCode).Select(i => i.OrderByDescending(j => 
j.OccurDateTime).FirstOrDefault()).ToList();

//ef 分组 排序 之后取所有数据
List<InstrStateDetail> listGroupPost = this.Select().GroupBy(i => i.InstrCode).SelectMany(i => i.OrderByDescending(j => 
j.OccurDateTime)).ToList();

//not in linq
List<InstrStateDetail> breakInstr = bllInstrStateDetail.GetBreakState();
var xx=(from c in measStateDetail where !((from d in breakInstr select d.InstrCode).Contains(c.InstrCode)) select c).ToList()

//not in ef
listSP= query1.Where(m => !query2.Contains(m.ETPRS_CODE)).ToList();