c# - 如何在 Fluent LINQ 中使用 or 子句进行连接

Question

我正在尝试连接两个表。

TSQL 将是:

SELECT * 
FROM User u INNER JOIN Hierarchy h ON u.OrganisationId = h.OrganisationId 
   OR u.OrganisationId = h.OwnerOrganisationId

我搜索过，没有人能用流利的方式回答这个问题。我能想到的最接近的是:

var join1 = context.User.Join(context.Hierarchy, u => u.OrganisationId, h => h.OrganisationId, uh => new {u, h});
var join2 = context.User.Join(context.Hierarchy, u => u.OrganisationId, h => h.OwnerOrganisationId, uh => new {u, h});
var desiredResult = join1.Union(join2);

但这似乎效率非常低。

Answer 1

语法流畅

var orJoin = context.User.SelectMany(
                u => context.Hierarchy.Where(h => u.OrganisationId == h.OrganisationId || u.OrganisationId == h.OwnerOrganisationId),
                (u, h) => new { u, h }
             );

---

查询语法

var orJoin = from u in context.User
             from h in context.Hierarchy
             where u.OrganisationId == h.OrganisationId || u.OrganisationId == h.OwnerOrganisationId
             select new { u, h };