Join 子句中其中一个表达式的类型不正确。对“GroupJoin”的调用中的类型推理失败。
var query = from d in db.d_necro
join g in db.Graves
on new { d.graveno, d.garea } equals new { g.gno, g.FgrId } into temp1
from g in temp1.DefaultIfEmpty()
join k in db.GraveKind
on d.gakind equals k.gkId into temp2
from k in temp2.DefaultIfEmpty()
select new
{
d,
g,
k
};
