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Entity framework 4 EF 4.0 Linq到Enity查询_Entity Framework 4_Linq To Entities - Fatal编程技术网

Entity framework 4 EF 4.0 Linq到Enity查询

Entity framework 4 EF 4.0 Linq到Enity查询,entity-framework-4,linq-to-entities,Entity Framework 4,Linq To Entities,大家好,我需要在Linq中将这个SQL查询复制到实体 select * from Subscriber a inner join User b on a.UserId = b.Id where b.Username = 'Name' 也许有人能帮上忙。试试这个: var query = from s in context.Subscribers.Include("User") where s.User.Username == "Name"

大家好,我需要在Linq中将这个SQL查询复制到实体

  select * from Subscriber a
  inner join User b on a.UserId = b.Id

  where b.Username = 'Name'
也许有人能帮上忙。

试试这个:

var query = from s in context.Subscribers.Include("User")
            where s.User.Username == "Name"
            select s;
假设订阅服务器具有引用用户实例的导航属性User

如果您想使用不需要的连接,可以将其用于内部连接:

var query = from s in context.Subscribers
            join u in context.Users on s.User.Id equals u.Id
            where u.Username == "Name"
            select new 
                {
                    Subscriber = s, 
                    User = u
                };
或者,对于左外连接:

var query = from s in context.Subscribers
            join u in context.Users on s.User.Id equals u.Id into x
            where u.Username == "Name"
            from y in x.DefaultIfEmpty()
            select new 
                {
                    Subscriber = s 
                    User = y,
                };

是否有其他方法可以做到这一点,而不包括好奇您是否希望加载用户数据?SQL查询使用*加载它们。如果只需要没有用户日期的订户数据,可以删除Include。一旦需要,用户数据也可以延迟加载。我的意思是var query=from s in Subscribers join u in Users on s.UserId等于u.Id select new{…}