[急]Linq求助
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悬赏园豆：5
[已解决问题]
解决于 2008-08-29 09:00
<P>小弟刚着手学习Linq,脑袋好象有些转不过来弯,大家帮忙写个语句吧,谢谢了,表结构如下:</P>
<P>BigClass表<BR>b_id name<BR>1 软件工程<BR>2 软件测试<BR>3 数据库开发</P>
<P>News表<BR>id title content time b_id(外键)<BR>1 title1 fasdfs null 2<BR>2 title1 fasdfs null 1<BR>3 title1 fasdfs null 2<BR>4 title1 fasdfs null 3<BR>5 title1 fasdfs null 2<BR>6 title1 fasdfs null 3<BR>7 title1 fasdfs null 1</P>
<P>查询出如下结果:<BR>b_id name number<BR>1 软件工程 2<BR>2 软件测试 3<BR>3 数据库开发 2</P>
<P>SQL语句实现很简单:<BR>select b.b_id as id,b.name as name,count(n.b_id) as number <BR>from news as n,bigclass as b<BR>where n.b_id=b.b_id<BR>group by n.b_id,b.b_id,b.name<BR><BR>由于刚开始学Linq,希望大家帮帮忙写下实现这个功能的Linq,谢谢了!</P>
最佳答案
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var query = from b in db.BigClasses
join n in db.News
on b.b_id == n.b_id
group new {b,n} by new {b.b_id,b.name} into g
select new {Id = g.Key.b_id,Name = g.Key.name,Count = g.Count()}
上面的是采用inner join 的连接方式
下面的是采用标准SQL的连接方式，也就是你写的那种
var query = from b in db.BigClasses
from n in db.News
on b.b_id == n.b_id
group new {b,n} by new {b.b_id,b.name} into g
select new {Id = g.Key.b_id,Name = g.Key.name,Count = g.Count()}
其他回答(3)
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mark，我也想知道
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var v = from b in db.BigClasses
select new {
Id = b_id,
Name = name,
Number = db.News.Count(x => x.id == b_id),
};
0
修改一下楼上的。
var query = from b in db.BigClasses
join n in db.News
on b.b_id equals n.b_id
group new {b,n} by new {b.b_id,b.name} into g
select new {Id = g.Key.b_id,Name = g.Key.name,Count = g.Count()}
楼上的正解。
