Linq的专栏（选择...）声明

Question

如何在MS SQL中编写与此子选项等效的linq语句：

... WHERE
tblXref.Organization_Id IN (SELECT Organization_Id
                   FROM AppUser au INNER JOIN [User] u ON au.User_Id = u.Id
                   WHERE u.Username = usernameVariable)

Answer 1

嗯，单独编写内部查询可能更简单（记住你不是执行查询）：

var innerQuery = from au in db.AppUsers
                 join u in db.Users on au.User_Id equals u.Id
                 where u.UserName == userNameVariable
                 select au.Organization_Id;

var query = from tblXref in db.CrossReferences // or whatever
            where innerQuery.Contains(tblXref.Organization_Id)
            ...;