我正在尝试使用 LINQ 左连接三个表。我的 SQL 工作如下：
Select j.Id, u.FirstName , u.LastName, u.Role
From Job j
left join JobTranslator as jt on j.Id = jt.JobId
left join JobRevisor as jr on j.Id = jr.JobId
left join [User] as u on jt.UserId = u.Id OR jr.UserId = u.Id
Where u.Id = someID;
我可以让它与两个连接一起工作，如下所示：
IQueryable<Job> jobs =
from j in _db.Jobs
join jr in _db.JobRevisors on j.Id equals jr.JobId into jrs
from jrResult in jrs.DefaultIfEmpty()
join u in _db.Users on jrResult.UserId equals u.Id into jrU
from jrUResult in jrU.DefaultIfEmpty()
where jrUResult.Id == userId
orderby j.Id
select j;
但是当我尝试加入我最后需要的表时，它不像下面那样工作。
IQueryable<Job> jobs =
from j in _db.Jobs
join jt in _db.JobTranslators on j.Id equals jt.JobId into jts
from jtResult in jts.DefaultIfEmpty()
join jr in _db.JobRevisors on jtResult.Id equals jr.JobId into jrs
from jrResult in jrs.DefaultIfEmpty()
join u in _db.Users on jrResult.UserId equals u.Id into jrU
from jrUResult in jrU.DefaultIfEmpty()
join u in _db.Users on jtResult.UserId equals u.Id into jtU
from jtUResult in jtU.DefaultIfEmpty()
where jtUResult.Id == userId
orderby j.Id
select j;
有人有什么想法吗？
From Linq - 多个（OR）条件的左连接 :
IQueryable<Job> jobs = (from j in _db.Jobs
join jt in _db.JobTranslators on j.Id equals jt.JobId into jts
from jtResult in jts.DefaultIfEmpty()
join jr in _db.JobRevisors on jtResult.Id equals jr.JobId into jrs
from jrResult in jrs.DefaultIfEmpty()
join u in _db.Users on jtResult.UserId equals u.Id into jtU
from jtUResult in jtU.DefaultIfEmpty()
where jtUResult.Id == userId
orderby j.Id
select j).Concat(
from j in _db.Jobs
join jt in _db.JobTranslators on j.Id equals jt.JobId into jts
from jtResult in jts.DefaultIfEmpty()
join jr in _db.JobRevisors on jtResult.Id equals jr.JobId into jrs
from jrResult in jrs.DefaultIfEmpty()
join u in _db.Users on jrResult.UserId equals u.Id into jrU
from jrUResult in jrU.DefaultIfEmpty()
where jtUResult.Id == userId
orderby j.Id
select j
).Distinct()
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