Question

左连接 linq to sql 分组求和怎么写

Answer 1

假纳败设 A 和 B 是两个集氏颤合, A要做外链接B, 连接条洞核颤件A.SID=B.SID

var result = from a in A
join b in B on A.SID equals B.SID into G
from g in G.DefaultIfEmpty()
select new
{
.....
};