c# - Linq 的 Column In (Select ...) 语句

Question

您如何编写一个 linq 语句，在 MS SQL 中执行与此子选择等效的操作：

... 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

好吧，单独编写内部查询可能更简单（记住您没有执行查询）：

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)
            ...;