EE left join

lihongyang0453

于 2020-12-03 13:27:56 发布

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var heatstationNames = from h in db.T_ES_EnergyStationInfo_HeatStation
 join p in db.T_ES_EnergyStationInfo_HeatStation on h.ParentId equals p.ID into leftP 
 from tt in leftP.DefaultIfEmpty()
 join o in db.T_ES_EnergyStationInfo_FE_HeatStation on h.ID equals o.HeatStationID join g in db.T_ES_EnergyStationInfo_FE_Group on o.FK_GroupID equals g.ID
 where g.ID == ID
 select tt==null?h.Name:tt.Name+"_"+h.Name;