Linq to Entities Group 之后是 Min

Question

我想编写以下 SQL 作为 Linq to Entities 语句

select min(enddate), Code 
from t1
inner join t2
on t1.t2id = t2.id
group by Code

到目前为止我所拥有的是

var data = ctx.t1.Join(ctx.t2,
                        one => one.t2id,
                        two => two.Id,
                        (one, two) => new {one, two})
                    .GroupBy(onetwo => onetwo.one.t2id)
                    .Min(onetwo => WHAT GOES HERE?);

我认为我唯一缺少的是 WHAT GOES HERE? 中的内容。我可能是错的，完全误入歧途，但据我所知，这是我唯一缺少的东西。知道我能做什么吗？

Answer 1

您应该使用 Select 而不是 Min，否则您将只能 return 一个值。例如，像这样：

var data = ctx.t1
    .Join(ctx.t2, one => one.t2id, two => two.Id, (one, two) => new {one, two})
    .GroupBy(onetwo => onetwo.one.t2id)
    .Select(x => new 
    {
        Code = x.Key, 
        MinDate = x.Min(g => g.one.EndDate) //This may need to be g.two.EndDate
    });

Linq to Entities Group 之后是 Min

Linq to Entities Group by followed by Min

linq-to-entities

entity-framework

group-by