Linq 外连接

记录一下linq外连接写法

var result = from a in OverViewInfo
			join city in Orgs on a.CityId equals city.Id into gcity
			from kcity in gcity.DefaultIfEmpty()
			join mcountry in Orgs on a.CountyId equals mcountry.Id into gcounty
			from kcounty in gcounty.DefaultIfEmpty()
			select new { a,kcity,kcounty};
			
result.Dump();  //linqPad调试